aceez71

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I just bought this car. 1987 TPI 350 Camaro. The previous owner said it was his daily driver and a couple months ago out of the blue it started running terrible and eventually wouldn't start unless you hold the pedal to the floor, then it will only run if you pat the gas, but will not stay running long it spits sputters and will barely run eventually it will die. He took it to the dealer and was told they could replace parts til it ran right possibly costing $1000 so he sold it to me. I have checked the fuel pressure, tps adj, injector impedance, all check good. Cap and rotor look new as do the wires, the firing order is correct. I have swapped the mass air flow sensor, esc module, coil and ign module with parts off my running S-10 350 TPI. Fuel pressure is at 43 and consistant during cranking. The iac will buzz if you ground the diagnostic pins but i haven't removed it and looked at it but i don't know if it can cause these symptoms. I have heard leaky injectors can cause this but usually only when warmed up this is happening while cold or warm if i can keep it running that long. My plan is to check the egr and look for vacuum leaks but its hard cause i cant keep it running long enough to test this alone. Any and all suggestions greatly appreciated. ps i also unplugged the cold start injector no change. Pulled #2 plug smelled of gas.

jv9999

iTrader: (1)

Sounds like a bad injector to me. How fast does the pressure drop when you turn the key off?

aceez71

iTrader: (1)

I didn't actually time it but it stayed up there a while. During swapping out other parts 20 minutes or so it was still 20 psi. How long should the pressure stay up there.

jv9999

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That sounds OK. Have you checked the compression? That might be a good next step. Also, make sure the injectors on both sides are firing. Either with a noid light or the long screwdriver to the ear.

aceez71

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Ok
I checked all injector plugs with a noid, I know each bank is tied together but i wanted to make sure all were getting a pulse. All checked good. One thing though, before i started to test them i disconnected all the injectors, i reached in through the window turned the key and it tried to fire up without any of the injectors connected. I didn't disconnect the 9Th. (I have a spare should i replace it,) could it be flooding the thing out while starting and dumping fuel while running causing the whole problem. I have a new set of 24# blue tops on the way but if its the 9th i'd like to either eliminate it all together or get it workin properly. Is it possible to start the car without a cold start injector. My S-10 is running an 89 chip so the cold start injector has been removed and blocked off. Will an 87 start at all with it removed and blocked off or do i need to use my spare and see if i have the same results.
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PS I'm checking the compression tomorrow night.

jv9999

iTrader: (1)

Yes, it will still start. But you'd need to disconnect fuel from it to really test your theory. That's not so easy to do. Compression is good to check. Have you looked at the EGR? If it's stuck open it won't idle.

With your pressure holding, I'd be thinking something other than injectors. Even with one or two bad ones, it should idle. How's the vacuum?

aceez71

iTrader: (1)

I can't keep it running long enough to check it. I'll try again tomorrow.Can i just use a vac pump to see if the egr holds vac or is there better way? I havn't checked the factory manual yet.

jv9999

iTrader: (1)

The EGR won't hold vacuum if it's closed, so I guess that's a worthwhile test. It would be better to remove it and take a look. But that means taking off the upper plenum. You might try plugging the EGR vacuum line for now. It could be hooked to manifold vacuum which would keep it open

Can you keep it running at 2-3000 RPM? Is it smooth when it's running? Any smoke? Backfiring? There's no big vacuum leaks? PCV line? Brake booster line?

Firing order right? Timing right? There's not a lot that will keep it from idling at all.

aceez71

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Ok heres whats new for tonight. I tried messing around with the egr didn't get anywhere fast, So i started looking for any and all vacuum lines and still found nothing. So i decided to remove the plenum and found the vacuum line that goes from the egr solenoid to the bottom of the throttle body and on to the vapor cannister was worn in two where it rubs against the front fuel rail crossover tube. I plan on repairing tomorrow and getting some new gaskets do you think a vacuum leak here could cause the problem i'm having. Also i double checked fuel pressure and it is 42 and when first cranked it drops to 36 for a split second then immediately back up to 42 and maintains during cranking, is that normal.

jv9999

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Sorry, but it's not likely the EGR vacuum leak is the problem. It's not helping anything though. The fuel pressure sounds OK to me.

aceez71

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Didn't think so. Well i plan on removing the dist and checking #1 at tdc and making sure it hasn't jumped time, And doing the dreded F body compression check. By the way when i do get it to run i have to hold it at about half throttle and it spits and sputters has a crackeling sound and sometimes backfires, although i cant really tell if its in the plenum or the through the exhaust but the muffler was split when i got it. If i let off the gas it dies immediately. And by the way thanks for all the advise it helps not getting tunnel vision.

aceez71

iTrader: (1)

I just lppked under the car i thought the muffler was split but the exhaust system looks good.
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Looked

BluFBdy

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have you checked the timing at all? is it possible that it could be sooo bad that it wont stay idling?

aceez71

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Yes it was at 6 degrees but i moved it around trying to see if i could get better results. I'll have to reset the timing once i put the plenum back on. Tonight i checked the egr out as per the gm service manual and it check bad. I have a spare on one of my spare tpi intakes and will install tomorrow. One other thing i did find was a port on the back of the egr solenoid with nothing connected to it, if anyone has an 87 and could check where it needs to run to i would greatly appreciate it. BTW the solenoid passes per the manual. I just can't believe how crappy this thing will barely run. Going back out to block the egr temporarily so i can start a compression check. We'll see how it goes.

aceez71

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OK Heres what saturday brought. Removed egr replaced with spare off another tpi intake i have. Checked passed gm factory manual tests. Checked compression i cheated a little and only checked 1,3,5,2,4,6 all around 140 -150 psi. Reinstalled plenum and connected everything. Tried to start wouldn't start came very close and sounded different than before but i didn't try to start it by holding the pedal to WOT like i have been Its pretty late so ill triple check timing tomorrow
So far i've checked:
Vacuum-all lines look good, repaired hole in ported line from throttle body
replaced egr that wouldnt move with vacuum pump attached
fuel pressure 42
firing order correct
spark good
compression good
no codes
smells like raw gas after several attempts at starting
plugs look fouled but have spark figured they're good enough to get running
I'm pulling dist tomorrow to see if the gear looks good etc
Any suggestions!!!! Graetly appreciated

85irocz355tpi

Are you sure the maf is good. I guess if you get no codes then it should be good but you never know. I toasted the distributor gear in my tpi 355 once and it ran like crap spitted sputtered and backfired. When it broke the tach started jumping around not even close to where the motor was at. does your tach do that. try and start it with ether. if it runs good with that then it could be bad fuel or something in the gas or something else with the fuel delivery. Maybe it is giving it too much fuel. I'd like to help if I can but I need some more info. Could it be in the ecm or prom.

JP86SS

iTrader: (1)

Plug the PCV at the throttle body to be sure its not stuck open and acting like a large vacuum leak.
Also check the vacuum booster is not leaking.
Plug stuff that you don't need until you find the problem item.
Might shed some light and is easy to do with a bolt.

91chevywt

To me, i have narrowed a couple things down in my head.
1st-You have a vacuum pump, so maybe try removing lines completely and plugging one end w/ a finger or tape and hooking the pump to the other end..this will definetly tell if you have a vacuum leak. Usually you need a substantial vacuum leak for a no-start..
2nd-Bad Fuel. Try siphoning some or hook up hose to test port and turn key on to collect some. try measuring volume for certain amount of time and compare to specs if you have them.
3rd-Engine mechanically sound? guy says it was a daily driver...but started running like crap. You may have good compression, but if you have rounded cam lobes,bad lifters, bent pushrods, youll still have a dead cylinder. maybe remove valve cover and look at valve operation.
Oh yea, could the catalytic converter be plugged? leaky injectors may have made a rich condition and toasted it...see if it rattles or anything like that

aceez71

iTrader: (1)

OK
Just to answer a couple posts with one.
The tach is going crazy I had to double check it with my scan tool to make sure i wasn't seeing things! Also when i can start it, usually with my foot to the floor (clear flood mode) The cat does sound like its crackling a bit the exhaust seems so loud i thougt the muffler was split open but it looks ok from the sides and bottom. So may be a multiple problem I will pull the dist this afternoon after the games and check the gear the rotor position with #1 at TDC and not 180 out etc. And again thanks guys and or gals i really appreciate the help i bought this as a Christmas gift for my wife and am secretly working on it.

aceez71

iTrader: (1)

Ok
Put No. 1 at TDC on compression stroke, verified with compression guage while turning balancer with a ratchet.
Removed distributer-gear looked good and ( like a dumb a** i pulled the dist out before noting if the rotor was correct or 180 out. When i pulled dist out it was dripping oil or so i thought, I just set it to the side and since the oil pump hadn't been moved i put it back in to see if it was at least pointing to #1 it was.
Went to parts store for a new gasket,pulled dist out to install gasket dripping oil again. Then it dawned on me the bottom 2" should not be wet since i havent started it.

Knowing the oil level was correct before i ever started it the very first time. I checked the dip stick and you guessed it 2 to 3 quarts high.

In the process I also found the vacuum line (The big fat one) from the throttle body to the purge solenoid was just laying there !

Should i change the oil and try starting it again or should i tear everything apart and replace injectors.

I know this is long and drawn out but i want to be clear! Thanks everyone!!

85irocz355tpi

being that much over filled with oil the rings might be shot. I hope not for your sake but My friends wife overfilled there fullsize chevy truck with 305 about that much and it smoked the rings. You can pull the injectors and have them rebuilt for about $20 a piece. I would try plugging that vacuum line for now to see if that helps.
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also if you get it running and it smokes like hell from the rings being bad you can take two capfuls of tranny fluid one for each throttle bore and dump it in the throttle body. The tranny fluid will help the rings to swell up and seal.

aceez71

iTrader: (1)

I hope the fuel in the ol hasn't done that. When it has started its been briefly.
I'm really reluctant to do anything besides drain the oil, and maybe pull the 9th inj out and check per the manual to make sure thats not whats dumping fuel and follow that up with pulling the fuel rail loose with the injectors in and put small jars under them n see if they're just dumping fuel all the time. I read that proceedure in the factory manual somewhere. I just don't don't see why the fuel pressure doesn't drop any faster than it does. Is it possible with vacuum leaks and timing off there could have been that much fuel dumped with it just not starting and staying running.

aceez71

iTrader: (1)

OK
Heres the latest.
Replace injectors with new ones.
checked fuel pressure after install. 42 and only dropped to 30 after 2 hrs.
Reinstalled dist with #1 at TDC compression stroke.
Checked firing order.
checked all vacuum lines with gauge.
Attempted to start car fired up but would not idle with my foot off the gas just slightly pressed.
As it warmed up ( temp seems to rise quickly)it got worse and worse, will not idle as soon as you let off the gas its off!
After keeping it running a while i looked out back and there are chunks of cat in the drive. Could the leaking injectors have clogged my cat and and muffler. The rear of the car was extremely hot and the fuel tank was hissing at the cap SCAREY loosend to bleed off. I think the muffler was heating the tank excessivly.

Plan to take to my friends muffler shop remove the cat for now and straight pipe muffler until i get this solved.

aceez71

iTrader: (1)

FIXED IT!!!!!!
After almost losing my mind i finally got it!
Leaking injectors while previous owner had it, fowled the plugs, filled the cat with raw gas and eventually quit running all together. GM told him it was an electrical problem! When i got it i did the usual fuel pressure checks timing spark etc. All the while the engine crankcase was also filling with gas that was pouring into cylinders from the leaking injectors that held pressure for at least 30 mins. I replaced a faulty egr fixed two vacuum leaks and installed new injectors. The car would still not run unless i forced it by applying throttle. Turned out the cat came apart and the chunks that didn't make it out of the tail pipe clogged the muffler causing it to die whenever i let off the throttle. Finally i removed cat leaving exhaust open and replaced plugs ( after checking and rechecking spark etc.) it started like a new car, according to the snap on scanner its running a little lean but the chip still thinks the injectors are 22# (plus i found the large vacuum line at the cannister off again !) the new blue tops are actually 24# ill post results if anyone is interested and any additional suggestions appreciated.

Lessons i learned:

Do the leakdown test per the GM manual (i would have seen the gas pouring out of the bad injectors!)

Leaking injectors can ruin an exhaust system.

Fuel fouled plugs will never again fire correctly!!!!

Remove rodents from newly acquired cars that heve been sitting awhile!!

And finally thank you all whom replied, it really helped me re-hone my TPI skills i havn't used since my S10 tune port conversion. THANKS!

jv9999

iTrader: (1)

Congrats! Look at all you learned. It's like a puzzle. It sure feels good when you figure it out.

aceez71

iTrader: (1)

Yep!!! Thanks again!!

tlgrooms

Glad ya got it fixed. I have a '91 RS and went thru this same nightmare. Replaced all kinds of stuff and was pulling my hair. Finally figured out it was the darn catalytic converter. It was stopped up so bad the exhaust had no where to go. Replaced it and the car runs like a champ now, even with 250,000 miles.... I bought it new and other than this and a few very minor things it has been a hell of a car. Going to have to replace my starter this weekend. A mechanic I had looking at it when I was having this trouble tried to start it so many times he screwed up the starter.

aceez71

iTrader: (1)

Yea my starter was hanging up when i was troubleshooting mine, hope it lasts a little while longer!