fulo

Let me present you the baisc concept. This is not the for the engine I have on my camaro. Is sone else. But I really need some advice. I am more in to the old set up of carbs and distributors. SImpel and realible. But this time I have an fuel injected engine that need fixing and I would like to tackle it.

At the begining, the car started fine and run, but sporadically it will hesitate under load. It did it randomly. This happened more frequenly with the AC on.

At first, I though It could be something a vacuum leaks. Since I have a severe valve cover oil leakage, I decide to take advantage and replace valve cover gasket, check intake manifold gasket, etc. I disconnected the battery, remover the Ignition Coil and Fuel pump fuse.

Took my time cleaning the parts, replacing the gasket and putting everything back together. I also took the change to clean the injector with some mild degreaser. I did it gently and quickly I did not soaked the injectors.

Then when I decided to start the car, the rough Idle I mention before suddenly became e heavy engine vibration. My first impression was that I must have put something wrong. So I discontented the battery and check the whole set up. Everything fine.

I checked the spark plugs, spark plug wires, and check for spark. Spark on each spark plug. No problem there. The ignition system seems to be working properly. I then decided to start the engine and disconnect the Crank Position sensor (engine stop as suppose too). Connected that sensor back and disconnected the Camshaft Sensor and no difference. That got me thinking, since the cam sensor has to do in the order of fire for the injectors.

I decided to start the engine and then disconnect the sparkplug cable from each (running) cylinder to detect a change. I noticed that nothing happened when I disconnected the last to cylinders.

I have spark on every wire, so I must be the fuel injection system, right? Connected everything back, started the engine (it vibrates heavy). I decide to disconnect the electrical connector, one at a time, for each fuel injector (kind like I did with the sparkplug wires). I noticed that nothing changed when I disable the last two injectors (same cylinder that where unaffected when disconnecting the spark plug wires).

So, in conclusion, I must have to ‘dead” cylinders. The ignition system seems to be working, and apparently the injectors might be faulty. But, then why northing happened when I disconnected the camshaft sensor. Since this sensor is the one responsible for determining when each injector fire the fuel to the intake manifold. Also, I did a compression check on each piston. Guess what. The two piston with the best compression where the two death ones!

This is where my puzzle is. I not very experienced with fuel injected engines. I do not have an OBDII scanner yet (I ordered one, and should arrive in a week). My real question is what should happen when you disconnect the camshaft sensor on a running engine?

Thanks for reading this LONG post. I will really appreciate all your opinions.

X22SE

Regards

3.8TransAM

Ummm you go on and on and never tell us what kind of car it is or what type of injection?

U'r sig says 87 TPI, but u mention OBDII and a cam sensor?

Cant help much if we have no clue as to what u are working on.

later
Jeremy

fulo

O.K. I hate to write it, but is not a 3rd gen. Is my wifes car, an isuzu rodeo 99, 4 cyl. X22SE 2.2 engine... But before you scream and yell at me "Dude, this is a 3rd Gen forum" hear me out.... There are very few (that I know) Izusu forums, and I need to figure this out. The wifey keeps complaining about gas prices and the sort. The rodeo consumes less gas, and since I got lay off, we are a little tight. So, please take this into account and share your ideas. I will really appreciated!

3.8TransAM

Ok since I am unemployed and feel your pain, I'll try and post what I know logically here.

It has 4 injectors. U can try ohming them out and see what u get.

They should all be within 1-2ohm of each other, any drastic changes there and u have found your issue(s)

Most newer vehicles will run with the cam sensor disconnected but will not restart. Or will start and run like garbage since the cam/crank is out of synch for fueling/spark

Most will not run without a crank sensor, nor will they even start.

Does it have wires or coil on plug? Test the wires for continuity and see what u get. If u see signs of water in the plug/coil hole, it could also be a sign of damage as they do not like moisture.

later
JEremy

fulo

The engine runs like crap. with either the CPS connected or disconnected. Only two cylinder down the work. I even get some back fired. I feels like something is not in sink there.

Some suggested that may be engine runs with the CPS disconected due to a close loop in ths ECM. ?

WHen I disconnecte the CRANK P.S. the engine stops. I know there is spark on all the wires. I even removed the injectors and fired the engine to see the myst. NO all mysting. Can the injectos be clean. Soak then in some citrus base degreaser?

I tend to lead for the CPS. I will have to wait until the OBDII scanner gets here.

Thanks for your feed back.

Evil 88IROCZ

Sounds like two dead injectors. Take a multi meter and check the ohms to make sure that they are within spec. If they are check the wiring conncectors for appropriate singnal (volts) from computer. Cleaning will not help if the ohms are bad it mean an internal failure of the injector itself and will have to be replaced.

8UpAFord

if you don't have a ohm meter just unplug the two injectors you think are failing and see what results you get. how many miles on the thing. if you're up in the 100s i'd say you injectors have problems, i think rodeo's have injector issues around the 100k mark i read somewhere. i had to slap some into my friends a year ago or so it fixed it up. Good luck

8Mike9

I had a Quad4 with 2 dead cylinders, only running on the waste spark. Q4 has a "tower distibution" thing that carboned up, sending inner holes to ground.

Funny thing is waste spark on the DIS systems seems to show like "normal" spark. Swap coil packs (if you have them) and see if problem cylinders move.

fulo

Thanks allot for all the feedback. One thing I have to say is that people here rock.

REgarding the previous tread, I have strong spark on all wires! It has to be either de CPS or the injectos. Havent had time to hcek it. Waiting for the OBDII for comfirmation. I will keep you all posted.

THANK and keep em comming!

FactoryFreak

iTrader: (2)

The engine will run just fine with or without the cam position sensor, all that sensor does is sequence the injector pulses. Without it the engine will resort to bank fire like a an early fuel injection system. If the cam sensor is faulty it will set a code though, but it won't hurt the engine or how it runs.

TPIgirl

Did you check for broken valvesprings or rockers/followers?

fulo

Thanks for the feedback. I should have an ODBII scanner by this week.

I must mention that i did notice a little back fire the las time I started. But it was when starting. No backfire once in idle. This lead me to believe that the CPS cab ne faulty, since I am pretty sure the Ignition is OK. ALso, there is strong emission odor. This leads me to believe that might be out of sequence.

I have not check the injector with an Own meter, but soon will. I wll keep all posted. One thing I have to say, DONT BUY A RODEO.

MattODoom

iTrader: (1)

I had a really rough idle on my GTA when I got it, and it was down two cylinders as well... the two cylinders were next to eachother and it turns out someone before me had put smaller bore head gaskets on it(305 maybe? its a 350) and the headgasket had blown out between the two cylinders giving them both no compression. Have you run a compression check on the cylinders? I could not figure out what it was for the longest time... I thought like you it was ignition, so i replaced coil, cap, rotor, plugs, wires but I had spark to all cylinders. Then I check the compression and problem solved.

fulo

thanks for the insight. I did check the compression. INdividally and compression is fine. I am possitve I do not have a broken head gasket.

I also checked the cam and lifters (since i had to change the valve cover gasket at the very begining). THe look nice.

Once I get the OBDII, I will be able to narrow it down more. I will keep all posted.

THanks

fulo

Hi to all, I have finally manage to get some things done, I landed a temp job, so my time was compromised.

I did check the resisitance for each injector. The haynes book indidacted that the resistance for 2.2 liter engines should be between 11.5 to 12.6. 3 of the cylinders were in range (12.4 ohms). Only one was above range (12.9). I dont know if 0.3 ohms makes a big difference on the ijector performance.

I then decided to check the voltage going to each injector while the engine was running. In the two original cylinders that were having combustion, the voltage was about 5, on the two cylinder absent of combustion, the voltage going to one injector was 2 and on the other was 1.8. Keep ion mind that I can disconect the to eletrical wires going to this two injectors and there si no change on engine idle.


Also, I notices that the check engine ligfth flashes continuously. I just recieve the OBDII form Auto Tap. Is the one tha you connect to your PC. I will install it and see what code I get.

My prognosis so far is iether a faulty ECM (PLEASE NO!!!!) or one of the Sensors (CPS or the CRPS).

Thanks for your previous Feed back.. And PLEASE keep sharing those thoughs.

Can wait to get this car fix, so I can go back to my 87 camaro!

fulo

Folks, I an pulling my hair. I got the OBDII, connected it and got some codes.. but what crappy codes!!

P 0300 =Radom Multiple MisFire
p 0303= Random Multiple Misfire Cyl N0.3
p 0402= EGR Excesive FLow

I honestly tough that I will get a code egarding the Cam Postion Sensor, but No sir.. I got this other ones and know I am very puzzled.

The car does show the misfired issued. The last two cylinder are not getting fuel from the injectors. I know this because the voltage going to the last two injector is well below 5.0 Volts, and i can literally disconnec the electrical connecto to the last tow injector and nothing happens. The engine keep indling like ****.

Another issue could be that the ignition coil is damage, but could that creating this symptoms.

I hope there is a soul out there that can help me clear this things.. this is one of the reason I prefer old style set up (mechanical carb and independent ignition).

PLEASE HELP

Vader

In general terms, most EFI systems operate in much the same way. Injectors are nothing but solenoid operated valves that admit fuel to an intake or runner. At a given fuel pressure, the longer the valve is open (energized), the more fuel will flow.

You have established that the injector coils are intact. The slight variation in solenoid coil resistance is negligible, and means nothing to the PCM. The ohmmeter has done its job.

However, your voltmeter may not be giving you the whole story. The '99 should use sequential injection - Even on an Isuzu. That means each injector is operated independently of the others. The PCM has an output transistor for each injector. Since Isuzu is a GM relative, I believe it uses sinking outputs like the rest of the Delphi systems. In other words, system voltage is applied to each of the injectors whenever the ignition is turned on. The outputs of the PCM simply provide a ground for each injector at the specified time and for a specified duration. And since the PCM switches this ground very rapidly, most voltmeters (your's included) cannot measure the voltage accurately. What your voltmeter is seeing is 12VDC being cycled very rapidly, not actually a varying voltage. Since most digital meters use sampling circuitry that requires some time base, the rapidly switching signal appears to the meter to be something less than 12V. An analog meter has a similar effect due to the natural dampening effect of the mechanical movement.

The proper method to test injector firing is with an oscilloscope. Using that, you would be able to see the 12VDC being switched (like a square wave) at varying frequencies and duty cycles. It is this duty cycle (duration the injector is turned on) that determines fuel flow rate. The fact that the meter you are using displays a different voltage probably only means it is interpeting a shorter duty cycle, and is trying to average it over the time base.

Because of this, about the best you can do with your meter is to test injector coil resistance (as you did), then check the supply voltage to each of the injectors. If each injector has 12VDC to a good ground with the ignition on, everything else is on the PCM side. Presuming the wiring between the injectors and PCM is intact, you need to measure the firing times (pulse width) of each injector and compare the results. Your AutoTap should be able to provide that. Mine does.

I'm guessing that you'll find some large variations in the injector pulse widths. The reasons for that can be varied, but having the injector timings to compare will be a big help.

fulo

>>>Because of this, about the best you can do with your meter is to test injector coil resistance (as you did), then check the supply voltage to each of the injectors. If each injector has 12VDC to a good ground with the ignition on, everything else is on the PCM side. Presuming the wiring between the injectors and PCM is intact, you need to measure the firing times (pulse width) of each injector and compare the results. Your AutoTap should be able to provide that. Mine does. <<< Vader

Vader, thank for the insigth. I am understanding the subject better.

In summation, this is my case:

1) I test each spark plug for fire. All spark plug are getting enough current to get the blue spark.

2) I tested each injector for resistance,and they all are in tolerance.

3) I test the compression on each Cylinder. Are are withing range.


4) The engine star, but is idel crapy. Heavy Vibration and idle. This vibration is reduce a little is I accelrate the engine.

5) I can disconnect the cable from both last cylnder (3 & 4) and the engine runns idles the same.

6) I can disconnect the electrical cable that goes to injector 3 and 4, and the egines runs the same (no difference).


7) I connected the OBDII from auto tap and got this codes:
ph 300 (radom/multiple misfire)
PH 303 MIsfire on Cylinder 3
PH 402(excesive flo detected, EGR).

8) If I disconneted the crank position sensor the engines stops. If I disconnec the Cam position sensor, nothing happes. The engines idles the same.

9) Ocasionally I hear a light backfire.

10) Heavy emission smells (unberned fuel)]

11) The Check engine ligth flashes continuously.


My prognostic seems to be that either the coils is back (this is a distrbuterless engine), or the ecm back, or a sensor is not working. Other than this, I have no clue as what to do.


Summing all this, where I can begining to tackle this issue.


One thing I have to say is that I apreciate all the support to this thread. On the isuzu sites (very few) i have not gotten any pointer. I am glad that in Thirgen, folks share their thoughs and suggestion. THanks allot.

Keep the ideas comming.

FactoryFreak

iTrader: (2)

The check engine light is flashing due to the EGR, because it is endangering the converter. Take a screwdriver or stephoschope and listen to see if the injectors in question are clicking. If you hear a clicking from them tap on them lightly with a hammer to see if they are just stuck. Seen this work many times on GM's. I would also invest in some BG 44k injector cleaner.
I still don't see why you assume it would have a cam position sensor code, when all the sensor does is control the sequential injection so it has nothing to do with the car missing.
Well since your this far you haven't got too many other opitions
You have spark and compression, pretty much only 1 other thing left and thats fuel. I would also recommend pulling off the egr valve and inspecting it, it may need a little cleaning.

fulo

Thanks for the thoughs.

The reason i keep lean for the Cam position sensor (CPS) is becuase is controlls the sequeatial action for the injectors. Since I have a misfire, there has to be something that is not in synch. Since I disconnect the electrcial connecto for the two last injectors and nothingh happend, and the CPS. Then I though that is not sending the signal to the injector to activate.

Know, since that PH 0300 & 0303, the multiple misire and the misfire on CYl 3, I am thinking that either the Crank Position sensor is faulty, or the Coil pack (distributerless) is damage. I know of no whay to test the coil pack.

May be I am looking a this issue with the wrong mindset (carb and independt Ignition).

On the EGR VAlce, I will inspect it, try to clean it, and if is unrepariable, change it. BuT I tend to believe that his is another isolate issue.


On cleaning the injectors. Could I just take the injector out an soak it on some citrus base degreaser?


An area that I am puzzle is the Misfire the the ECM seens. What could cause this in this type of engine?


Thanks for the though, I keep all posted on the progress!

RednGold86Z

iTrader: (1)

A cam position sensor is only needed during cranking to sync up in most software. The ECU can keep track of sync from then on. I would definitely abandon that route.

Sounds more like and injector problem or vacuum leak.

fulo

O.K. I will abandon my thing for a FAULT CPS. WHat I will do it swap a known got injector in the position of a bad one. If the injector is fautly, I should show clearly. What about soaking the injector on a citrus base degreaser? ANy body done something like this?

Thanks, keep all posted!

Vader

1. Are you absolutely certain the firing order is correct? Be very careful about reading the markings on the coil pack(s), since the numbering sequence is not necessarily 1-4. The secondary wires on the coil pack(s) may indeed be "1-4-2-3", or some variant.

2. What is the correct firing order? 1-3-4-2?

3. Do you have one or two coil packs?

4. What is the condition of the spark plugs?

If you have two coil packs, you can exchange them and see of the "dead" cylinders move. If you have a single coil pack all hope is not lost. Once you have verified the spark plug wires and firing order are correct, you can try to exchange the secondary wires to the opposite cylinders in the firing order. If you have a wasted spark system, the timing will still be correct.

Vader

You have already removed the injectors and tested them by cranking;

You have established that all of them are delivering fuel;

You are detecting the odor of raw fuel in the exhaust.

I would temporarily ignore the though of an injector problem and concentrate on the ignition system until you are certain it is intact.

fulo

+++++++++++++++++++++++++++++++++++++++++++
I did checked the Firing order on the coil back a while back. I am pretty sure they are in order, nontheless I will check again later.

Sadly, the goil pak is a single unit.

THe firing order is

1,3,4,2

The coil pack looks in good shape! In the haynes book they dont mention how to test it. Any ideas?

Thanks

fulo

O.K, but what else I can do here.

I have establishthat I get strong spark on all plugs. Computer detecs a miss fire on Cyliner 3, and then randonly, WHat coudl create this condition, since all is controlled by the PCM. The car electrical harness look intact. NOthing has been change, orignal factory radio. I am sure there is no short circuit, or the like. SInce the haynes manual does not show how to diagnose the Coil pack, what othe thing I can check??

Thanks

RednGold86Z

iTrader: (1)

I thought you said NOT all the injectors are misting? Do you mean they all spray, but some spray poorly? Or some just don't spray at all? Removing the injectors and cranking should show all injectors spraying well (albeit dangerous). Injectors can be serviced or replaced. I'd go ahead and swap them around and see if the symptoms follow the injectors.

The coil pack should have access to the 12v supply pin and the 2 grounding (firing) pins, but if it has a built in module, it may not be that easy. A parts store can usually inspect a module, but I don't know about your application.

The raw fuel smell can be from many things, such as a misfire fooling the O2 sensor, open loop rich operation from detected faults, static injector, lean misfire, ignition misfire, vacuum leak misfire, the list keeps going. It doesn't mean all injectors are firing by any means.

Good Luck

fulo

Folk, I am soooooo Happpppyyyy to let you all know that with the help of all a solution was found. Today, I was suppose to attend to a not too importnat meeting. I feelt a bit groggy from a BBW last night. I decided to stay in. WOke up, this my regular things, I decided to take a look on the rodeo. At that moment I though that the problems was either the coil pack, ECM, or the injectors. On this carr everything is soo expensive... the coild pack retail for about 170.00, the injector average about 45 pet unit, the freaking CPS is 225.00... I tell you.... what a rip off.


Anyways, I decide to takce the coild pack out to see if I could get some numbers so I could go to the web and find a page with information about this coil pack and how to Trouble shoot it!


First let me tell you is was HELL to remove that coil. WHO ENGINEER THIS THINGS... I was HORRIBLE... I was so mad at point.


Finally came off, took some mild decreaser, ligthly spray some on it, clean it, and saw the numbers and WHAT a surprise.. I almost could not belive it.. i got so anxious, that took 5 minutes off. Check the pictures, you will see!!!

RednGold86Z

iTrader: (1)

so.... was it the firing order drawing confusing you? Is that what we're supposed to see in the picture?? Did you put 1-3 and 4-2 together like on the firing order drawing? That'd do it.

All I4 engines that I've seen have a flat crank and paired center cylinders, which would mean 1-4 on a coilpack and 2-3 on the other. The coil packs fire in a wasted spark condition, where both plugs from one coilpack fire at the same time, but with only one plug recieving a lot of engergy since the other plug fired eaaasily in the exhaust air (thus wasted). It's not conventional electrical behavior.

fulo

Yes, it was teh firing order. Someone mentioned earlier in a post and got me thinking, then the OBDII pulled a misfired code.

The coil in this car is "buried" deep by the firewall, monther so close to the transmission. WHen I disconnected the wire to check for resistance and the like, i when by the HAYNES book to put them back in order.

Like I mention in the previous post, the coil pack was cover with dirt, and bein where i was, and and black, I coudl not see anything. So I just reference the Haynes book. Well, they have a mistake, it that mistake cost me on OBDII (well I needed one anyways) and many gray hairs.

But with the help of the member of thirdgen, the problem was solve.

This forum rocks!

thanks to all!

KiLLJ0Y

iTrader: (1)

have you condeded the fact that the injectors.. although pumping fuel.. could be stuck open and dumping considerable amounts of fuel.. enough to bog the hell out of cylinder?

mine did that..

wasnt until i took them to a shop that cleans and flow tests injectors that i found this problem.. cost was $35 per injector..

fulo

Problem Solve. Engine runs like a charm, no exhaust odors. It was order of the wires in the coil pack. See reply with picture
thanks!

Amigo

Greetings people. Well I just had the SAME exact problem. I've got a '99 Isuzu Amigo. Had all the same symptoms after replacing the wiring set ALL at once and then relying on Haynes to walk me through the rewiring. Man what a mistake this one time. After TWO used coil packs later, cause I had already discounted wiring and plugs, I finally decided to look up some websites. When I read about the two dead cylinders, which was what led me to believe that MAYBE the info on the Haynes was wrong, I went back and wired it as so and WHALA!!!! Smooth as butter again. Hey it's a good car, 186,000 miles on it. And by the looks of it, it actually prefers not to be messed with. I only changed the cables out of routine maintenance, not out of necessity.

Thanks for all the help guys!

Sincerely,

Amigo

fulo

Hahaha, awesome... I remenebr about that probelm!... great that it help othersw out!