Question about Cars & Trucks
HISTORY: 89 Firebird with a 92 Camero engine. V8 - 305 - 2 injector throttle body (tbi). Sat for 9 years in the driveway with a bad fuel pump. RECENT WORK: replaced fuel pump, cleaned fuel tank, removed old gas, replaced both fuel injectors with reman. from Advance. I rebuild the throttle body with a new gasket kit (didn't touch the fuel pressure regulator - but I have a gasket for that if needed), and replaced fuel sending switch on the firewall. Changed oil and oil filter. New drive belt. I have power at the fuel pump - it primes every time. The injectors work - both read the same when I test them with ohms meter, and both spray a mist of fuel (not a dripping spray). It starts fine several time, and starts great AFTER it starts once. But if it sits for a few hours, or a day, it sometimes (intermittently) will start sputtering and not run. She is turning over, and there is fuel being sprayed into the throttle body (fuel system has pressure) , AND there is confirmed spark - but she won't 'catch' and run smoothly. I've gotten it to start twice by removing the air filter and discon/recon the fuel injector wires, but this is after confirming that they were indeed getting signal AND spraying fuel. Weird thing is - after it is done with its temper tantrum, it'll start fine, catch every time, and run fine. I drove her for 20 minutes after her latest tantrum, and not one problem. I start a new job in a week, and need this car to get me there. Any ideas what could be causing this intermittent 'coughing'? Additional Details I forgot - brand new battery too. Engine doesn't run hot, or seem to be skipping. Once running, it does not choke out when I throttle up.
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Posted on Jan 02, 2017
SOURCE: buick lesabre nightmare
Need to get a scan tool and look at the data stream while it is running for alot more info.Also any trouble codes.Sounds like initially,the engine isn't getting any fuel.I would have a pressure gauge connected to the fuel rail on the engine,so i could monitor the fuel pressure while all this is going on.Items to look at on the data stream would be timing,what timing is the PCM commanding for the engine.Also,have you checked for continuos power feed to the coils during this no start condition,and fire at the plugs while cranking.You could possibly still have spark,but maybe it is extremely weak?I have seen bad ignition switches cause weird problems before too.Many things power up through the ignition switch,just a thought.Have also seen bad PCM's cause strange problems..38 volts is a little on the low side for GM.Usually see those at,at least .50 and up,and rise steadily while pressing the throttle,up to just under 5.0 volts.Potentiometer with 5 volt supply.Vacuum leak can be checked with engine running at a steady idle speed,spray brake cleaner all around the intake manifold and listen for engine speed change.
Posted on Jul 31, 2008
Please go to the crossfire injection forum to get some straight answers to the 82 corvette CFI system and how to troubleshoot it properly. There's a lot of misinformation given here, so much so, I don't know where to begin.
One thing is, the 82 corvette CFI does NOT have a MassAir Flow sensor system, it uses MAP and O2 mostly. The CTS sends a signal to the ECM telling it what the temp of the motor is and in turn the ECM controls the amount of fuel being dumped. On the older (orignal) CTS sensors, they have one wire and takes its ground from the threads. If any coorosion takes place, usually the CTS will report a cold engine and request lots of fuel.
To repair this issue, install one of the newer style CTS sensors that have two wires, one for signal and the other is ground.
Fuel pressure and vacuum leaks on any CFI motor play key roles. Set the FP to 14-15psi measured inbetween the TBs. The regulator is located on the rear TB and must be slightly moded to make it adjustable and can be done in a few minutes.
Posted on Mar 07, 2009
the injectors are fired thru the engine cotrol module but it gets its signal to fire from the pick-up located inside the distributor if you are loosing injector pulse only the ignition module is bad if you are also loosing spark when you loose injector pulse your pick up is causing the problem if you replace the pick-up i recomend you change the ignition module when doing so because they work together and you have to remove the distributor to change the pick-up
Posted on May 31, 2009
try bypassing the oil pressure switch on the back of the block behind the distributor, if there oil pressure switch goes bad it will do this. had one that drove me nuts trying to fix it then figured out I had to buy a book and low and behold thee it was 3 wire oil pressure switch you can't see between the engine and fire wall just behind the distributor and costs 8 bucks to buy new.
Posted on Jan 16, 2010
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