fkboatman

91 camaro tbi 5.0 w/ spd. car has no mods.
Starts up okay, drive away and spitts and sputters come to a stop searches for a idle then settles down, take off and have to ride clutch to go. you go to accelerate and car spitts and sputtrs from about 12-26 hundred rpms then runs great past there.when you hit 2300 rpms car starts to fall on it itself and has slight miss and loss of power. you go any where and let it hot soak and you start it up you have to keep it revved up past 2500 till it cleans it self up and runs ok or it dies. when it does that, the exhaust smells and will burn your eyes but no black or adnormal exhaust color. I HAVE REPLACED, o2, tps, pickup coil, module,injectors with complete rebuild of tbi, knock sensor. coolant temp sensor and air temp sensor, ignition coil, map sensor. I have had only one code come up which is egr,replaced it never had that code again. all tuneup stuff bein replaced also. DOES ANYONE HAVE ANY MORE IDEAS. thank you

RFmaster

Do you know what your fuel pressure is under load???

9 time out of ten symptoms that you are describing are related to low fuel pressure. Check it before throwing more parts at it.

//RF

fkboatman

I have driven car with fuel pressure gauge under wiper blade and never noticed go under 11psi

RFmaster

Hmmm - since you have reported a funny smell and EGR code it's possible that you have exhaust back pressure - clogged CAT??? How many miles do you have on the clock??

//RF

fkboatman

140,000, exhaust sounds good, does not sound any diferent then it did a yr ago but no i have not dropped the exhaust to look inside of cat. car has no noticable loss of power.

RFmaster

Fuel Filter ????
11 PSI is on low end of range that I would call acceptable. I also would perform FP 'deadhead' test. Pinch return line while measuring fuel pressure. It should zoom past 20 PSI with a good TBI pump.

//RF

fkboatman

I checked fuel pressure again. and now its at 10 psi idleing under load it drops to about 8, not happy know what that means time for a pump, strainer and filter.

fkboatman

ITS NOT THE PUMP. put new pump, filter, and strainer still same problem. pressure is at 12.3 any more bright ideas

RFmaster

I am trying to help you, but being remote makes it rather challenging - get a DVM... Lets make sure that ECM is not seeing something squirly.

Also, do you have access to a laptop with WinALDL or OBD1 scanner?

Otherwise, allow engine to fully warm up and at idle, 1200, and 2400 RPM measure the following voltages:
1) Measure CTS voltage (between yellow wire terminal and ground (black wire))
2) Measure TPS voltage (between terminal B (dark blue wire) and ground (black wire) )
3) Measure MAP voltage (between terminal B (light green wire) and ground (purple wire)

Measuring voltages requires 'back probing' through the back of the connector which requires carefully pushing a small diameter DVM test lead between weather insulator (rubber seal) and connector body openning (that houses respective pin) until DVM test probe comes into contact with connector pin. Do not puncture through the wires as this will destroy harness over time!!!

At idle
CTS (~85C) should read about 1.6Vdc
MAP should be between 1.5 and 2.0 Vdc (depending on engine vacuum)
TPS should be about 600 mV.

With no load MAP will remain more less constant across RPM range (high vacuum condition) while TPS voltage should increase (smoothly) from 600 mV at idle to about 4.5 Vdc at WOT.

//RF

lafountain

just a thought. have you checked the fuel pressure reg. ?

Jono4820

iTrader: (1)

Water in the gas? When the car runs bad is it getting hot? Shorted out wires on the distributer?(tach wire against firewall) Timming correct? Correct firing order?

RFmaster

I just went over original post and I have couple of questions:

1) When did these symptoms started (loss of power at 2300 RPM, unstable idle, heat soaking, etc)????
2) When was the last time you checked spark plug wires wires, how old are these wires???
3) Inspect inside dizzy hat. Do you see any brown - red deposits? How good is center contact? Does it make good contact with rotor pad contact?
4) Is your dizzy covered in dirt, or is excessively oxidized on the outside???
5) Inspect your spark plugs - what do you see????

//RF

LAFireboyd

iTrader: (3)

...to quote the master.

I've experienced a clogged cat, as well as helped a friend deal with, what also turned out to be, a clogged cat. And your car's symptoms fit the profile perfectly.

Other problems that share similar symptoms to a clogged cat tend to be ignition coil/module/dist. related. But you've already changed all that, before getting "bright ideas" from people, and nothing helped. Besides, given the way your car is running, if it didn't need a new cat before this happened, it's probably going to need a new one soon anyway. So why not check it out?

I know, it's frustrating when a problem isn't easy to solve, but you asked for assistance, and people are just trying to help. Cool?

fkboatman

New cap, rotor, wires plugs, coil, pickup coil, battery voltage to coil input, checked all grounds today and all are clean and tight. this problem started a week ago. egr valve is new today. when this first started car would run good then all of sudden started acting up and would just die if you pushed gas pedal. idleld in my driveway for 3 hrs with no problem, so i had module tested and it was bad so replaced and a couple of days later this started. so i pulled that module and put a ac delco one in just for giggles but has from the start would not run if hot soaked and missed at 2300 rpms before it died in the beginning.

RFmaster

The module you are referring to is the ignition control module inside dizzy, right????

Couple of things that can go wrong when EST gets replaced.

1) People do not remove old grease and clean-up mounting pedestal. Leaving old grease is a big no-no.

2) Too much dielectric white grease when installing NEW module. Module does not have a good thermal contact with dizzy body and may act up at elevated temperatures.

3) Flipping 2 pin connector from reluctor coil - this will result in weird timing over RPM range.

//RF