SPIKE

iTrader: (1)

car would start all the time! parked it last week and went to start it this weekend and it started but a little rough. then it quit,now all it will do is crank and run for about 10 seconds and die. while it was still running last week i did a complete tune up plugs,wires,cap,rotor ect. now im lost! have fuel pressure 45 psi and computer is putting out no codes except 12 which means every thing is ok. any tips, i have gone as far as my chilton manual leads me?

MDv6man

Check for spark. Probably a bad ignition module

SPIKE

iTrader: (1)

thanks il try that. thought i had spark because motor will run for 10 sec then die.

camaro_junkie

I don't have my shop manual at my side, but there is a diagnostic chart for that exact symptom. Perhaps someone can post it... I think Trickster has a whole bunch of those scanned in. And before TomP gets a chance I'm going to say, get the GM shop manual if you intend on diagnosing your car on your own at any time. It's invaluable and you can get it from www.helminc.com or ebay.

89V6FBIRD

Sounds like a huge vacuum leak, did you happen to knock off the vacuum hose that goes to the brake booster? I've done that before

SPIKE

iTrader: (1)

thanks i should get to play with it tonight after work. ill look for that manual the chilton manual is full of miss info for example it says to check tps voltage on pins b and c with throttle closed when its actually a and b. glad i know how a potentiometer works. i guess i could have knocked off a vacuume line i was so p.o. when it wouldent run i didnt look for the obvious. ill let you know.

SPIKE

iTrader: (1)

well i checked it out last night to no avail. no apparent vacuume leaks. tps set, cleaned tb, good spark (ouch)! hooked up vacuum guage got about 10 in while trying to start, wouldnt run long enough to get a good reading about 5-10 sec. still no codes except all ok. ill take any and all suggestions im at my whits ends.ordered helmic manual, hope it will help. any way to check mass flow? could this be a problem or would car run but crappy. not much experience on fi alawys been a carb guy. please any tips will help.

MDv6man

Unplug the MAF and see if it runs better. The ECM will use a default value to compensate. If it rums, the MAF is bad. Did you check the fuel pressure?

camaro_junkie

This is definitely a good idea in any MAF car. But, if the MAF is toast, does it start at all?

SPIKE

iTrader: (1)

fuel pressure is good 45 psi. disconnected most sensors including maf and no change. one thing i noticed is if i hold throttle open it will run longer but sounds like it runs on and back fires.

camaro_junkie

Bad gas perhaps? Any way water could have gotten in there? What about your timing? Did you disconnect the EST and check timing?

SPIKE

iTrader: (1)

just finished a tune up and was running fine after i set timing then parked it. week later when it wouldnt start. wont run long enough to re check it. shouldnt have changed. fuel could be an issue when i got car it sat for a year so i filled the tank with super and injector cleaner and im about through 1/2 tank of it. tank was about empty when i filled it.

camaro_junkie

I see that the Trickster (or whoever it is that has scanned the diagnostic charts) has not come through, so later this afternoon I'll get that chart for you.

SPIKE

iTrader: (1)

thanks camaro junkie i appriciate it.

Dale

iTrader: (12)

I belive mine pulls more then 10psi of vac.

Is the spark red, orange, blue, white??

Fuel filter?

SPIKE

iTrader: (1)

DALE SPARK WAS ORANGE. FUEL SEEMS TO HAVE GOOD FLOW WHEN I PULLED MY TEST GUAGE OFF OF LINE I ENERGIZED FUEL RELAY AND IT SHOT OUT A GOOD AMOUNT OF GAS. WAS GOING TO CHANGE FILTER AFTER THIS TANK OF GAS HOPING ALL CRUD WOULD BE OUT OF TANK.

Dale

iTrader: (12)

spark should be white, not orange.

You have spark issues.

SPIKE

iTrader: (1)

dale, coil or ignition control module? were would be the best place to start? or just replace both? can these ignition modules be pulled out and be tested at the store like the old ones?

Dale

iTrader: (12)

It could be cap not on all way.
Could be ICM or coil
Could even be the alt not putting out enough juice.
could be weak wires

Coil can be tested
ICM can be tested in most parts stores(5.5mm or 7/32 screws)

As to which first, I cant answer.

SPIKE

iTrader: (1)

new cap, rotor, wires and plugs last week or so. just looked at them all look good spark is orange when wire shorted to block but white when using old plug to block. just found out something new motor wont even try to start unless i hold open throttle then it pukes out.

Gumby

spark should be a bright blue to white.

camaro_junkie

Here's what the manual says to check:

Pre-check:
1. ECM and SES light are operating
2. Check for computer trouble codes
3. Check fuel system by performing Field Service Mode Check (not sure what this is)

General checks:
1. ECM grounds for being clean and tight
2. Vacuum hoses for splits, kinks, and proper connections, as shown on Emission Control Information label
3. Air leaks at throttle body mounting and intake manifold
4. Air leaks between MAF sensor and TB
5. Ignition wires for cracking, hardness, proper routing, and carbon tracking
6. Wiring for proper connections, pinches, and cuts

Engine starts but immediately dies:
1. Check TPS for sticking or binding or a high TPS voltage with the throttle closed (should be less than 0.7V)
2. High resistance in coolant sensor circuit or sensor itself
3. Fuel pressure chart A-7 (I can scan this in later if you need it)
4. Water contaminated fuel
5. EGR operation, be sure valve seats and is not staying open (see chart C-7)
6. Injector fuses
7. Ignition system (check distributor for worn shaft, bare and shorted wires, pickup coil resistance and connections, loose ignition coil ground, moisture in distributor cap)
8. If problem exists in cold weather, check cold start valve (see chart A-9)
9. Faulty fuel pump check valve (see chart A-7)
10. Check spark plugs for moisture, cracks, wear, improper gap (I think it should be 45-thou), burned electrodes, or heavy deposits
11. If engine starts but then immediately stalls, open distributor by-pass line; if engine then starts and runs OK, replace pickup coil (this must be the EST bypass on the firewall near the blower motor)
12. If engine starts and stalls disconnect MAF sensor; if engine then runs and sensor connections are okay, replace the sensor

Definitely try disconnecting the EST bypass. If you think you need one of these charts, let me know.

SPIKE

iTrader: (1)

thanks camaro junkie, there is some good info there. at least a couple of things i havent tried yet. ill try them tonight.

SPIKE

iTrader: (1)

camaro junkie your the man! got off my ego trip and decided to go down the list and check every thing off. well when i got to check plugs i thought why, they are new only about 50 miles on them. pulled them every one black and smelling like fuel. cleaned them up and motor runs. got codes 24 speed sensor and 42 timing so i reset timing must of bumped it pulling vac lines. reset ecm and only code 13 came up o2 sensor. also disconnected mfs and no change in motor. would both or one of these cause motor to run that rich to foul plugs also exhaust smelled of fuel. thanks man now ill sleep alot better knowing im getting somewhere. one last thing could weak coil cause this also.

Gumby

Both the O2 and MAF/MFS ae needed for the computer to adjust the fuel right.

KED85

Stick on a new coil.
SOUNDS LIKE your coil is becoming weak.
A weak coil will not allow the car to run, or operate correctly.
Your spark plug wire spark while testing MUST BE LIGHTENING BOLT BRIGHT WHITE
Try the plug wire test again.
Stick in a large paper clip into any easy access plug wire. Ground the plug wire somewhere. Wait until dark.
Check the color now.
Weakened coils cause all sorts of problems.
As you can see I remote mounted my coil in the back passenger side on firewall. A weak coil sure will allow plugs to foul out easier!

camaro_junkie

A bad O2 sensor will definitely cause your engine to run at an improper AFR, likely rich. The computer will revert to some back-up value of fuel to deliver.

Code 24 is only relevant if it is set when the car is moving. Otherwise, erase it and worry no more. Code 42 is set any time you disconnect the EST to set the timing. So reset the computer after you set the timing.

SPIKE

iTrader: (1)

allright guys sounds like a trip to the auto parts store for me.its friday am probably blow out of work early get parts and start messing with it. let yall know this weekend if i finde the culprit. i can almost smell victory

SPIKE

iTrader: (1)

thanks for all the help guys, car is running ! replaced coil $16. and o2 sensor $20.

Dale

iTrader: (12)

running correct now?

SPIKE

iTrader: (1)

dale, son is driving car daily said its running ok. i need to check it out to make sure its running the way its suppose to. going to add new k&n filter this weekend. still may need a little tweeking. as far as my son goes he thinks if it moves its fine! i really need to check the plugs to see if it is still running rich. ill let you know. thanks.

SPIKE

iTrader: (1)

just an up date for any one still reading. car is running great. new coil and o2 sensor. plugs are looking good (not running rich any more). still not sure what went first? well thanks for all the help. now the tranny is slipping a little. its alawys something.

camaro_junkie

Good to hear that you fixed the engine.

I assume that's an auto tranny?

SPIKE

iTrader: (1)

yup. auto tranny 700r4, iv rebuilt some old 350 and 400's but will probably take this one to the pros. well see how bad they stick me. transmission is shifting fine but takes forever to get car moving. allready tried the anti slip additives to no avail.

TomP

Lee Myles rebuilt mine; it lasted a year and a half. Cost = $1400.

Then a certified trans expert rebuilt it, and it's been screwed up ever since. (Slips going into 2nd) The guy was a friend of a friend of a friend who owed him a favor (you see how this goes), so it only cost me $400 (parts only).

If you've rebuilt trannies before, you'd be 100% fine with the 700r4. It's just got more parts. I assume you know where to get the ATSG manuals, but just in case, http://www.atsg.biz/cgi-local/shoppe...egories=action gives the list of books. But their website looks "cheesy" for ordering... I bought mine from http://www.naparts.com (although actually back then, they had no website, so I called them to order it.)

There's two manuals, one covers from 83 to 86, the other is 87 to 93. The GM Service Manual that Camaro_Junkie mentioned (yep he beat me to it! ) has a trans section that is almost an exact copy of the ATSG book, but the ATSG book has the updates and the service bulletins in it. (I have both)

And http://www.eastwoodcompany.com sells a video on how to rebuild the 700r4. One of these years I'll buy it... I plan on rebuilding this trans myself, because I certainly can't do worse than those experts did.

SPIKE

iTrader: (1)

can any one tell me why they made 2 different trannys v6 vs v8. i can find v8 trannys all day long. have one in my garage from a 88 pu. does any one sell adapters. if not and i get board soon i might buy a rebuild kit about $200 and try it. when i rebuilt my first th350 every boby told me i was nuts. way to complicated. so i bought a rebuilt kit and replaced all the parts that came with it. and the thing is still running today in my swamp buggy! i keep reading all these posts about nightmare tranny shop rebuilds on the 700r's. especially the cost. well sounds like i might have a christmas holiday project.