'88 won't idle - no codes either...
Thread Starter
Intermediate
Joined: Mar 2009
Posts: 46
Likes: 0
From: Berwick Pennsylvania
'88 won't idle - no codes either...
Hello all. My '88 will start and run ok for about 10 seconds, then die. Fuel pump, filter, injectors are all new, cap and rotor have been replaced.
The ECM shows no codes - not even code 12. Is it toast?
I can just barely keep the motor running if I goose it and keep the rpm's up around 1500, but I can't drive it anywhere like that.
Any ideas? Insights?
thx,
JR
The ECM shows no codes - not even code 12. Is it toast?
I can just barely keep the motor running if I goose it and keep the rpm's up around 1500, but I can't drive it anywhere like that.
Any ideas? Insights?
thx,
JR
Pro
Joined: May 2006
Posts: 637
Likes: 0
Hello all. My '88 will start and run ok for about 10 seconds, then die. Fuel pump, filter, injectors are all new, cap and rotor have been replaced.
The ECM shows no codes - not even code 12. Is it toast?
I can just barely keep the motor running if I goose it and keep the rpm's up around 1500, but I can't drive it anywhere like that.
Any ideas? Insights?
thx,
JR
The ECM shows no codes - not even code 12. Is it toast?
I can just barely keep the motor running if I goose it and keep the rpm's up around 1500, but I can't drive it anywhere like that.
Any ideas? Insights?
thx,
JR
Did it run OK before?
Shure you put on the wires in the right order?
Last edited by vette079; Jul 21, 2009 at 10:20 AM.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Check the plug wires. Sounds like the distributor is off a tooth if the wires check out. Did you pull the distributor? ..If you did get a hold of timing light and unplug the ESC connector for the advance and see how far your off while someone cranks the motor. Or pull the distributor cap and kick the crank around to the "0" mark and see what you got for a rotor position.
Thread Starter
Intermediate
Joined: Mar 2009
Posts: 46
Likes: 0
From: Berwick Pennsylvania
Does SES light pop up when you turn the key to the on position without starting?
Did it run OK before?
Shure you put on the wires in the right order?
Did it run OK before?
Shure you put on the wires in the right order?
It ran very rich. The plugs were sooty. Gas mileage was poor.
Firing order and wire position have been confirmed.
Check the plug wires. Sounds like the distributor is off a tooth if the wires check out. Did you pull the distributor? ..If you did get a hold of timing light and unplug the ESC connector for the advance and see how far your off while someone cranks the motor. Or pull the distributor cap and kick the crank around to the "0" mark and see what you got for a rotor position.
jr
Pro
Joined: May 2006
Posts: 637
Likes: 0
Would have been good with some pics of the connector, but it sounds like the ESC connector, can you find a loose connector in the big harness under the wiper motor somewhere where it might fit in.
The ses light popping up and now codes showing up sounds worrying.
Don´t have a manual for a 88, but try and dis and re connect the minus cable from the batt. and see if that changes stuff.
Try locate the ESC connector in the big harness first.
The ses light popping up and now codes showing up sounds worrying.
Don´t have a manual for a 88, but try and dis and re connect the minus cable from the batt. and see if that changes stuff.
Try locate the ESC connector in the big harness first.
Thread Starter
Intermediate
Joined: Mar 2009
Posts: 46
Likes: 0
From: Berwick Pennsylvania
OK, after locating the EST connector (the brown/black single wire connector near the brake booster), I disconnected it to check the base timing. It's set at 6 BTDC, spot on according to the emissions tag. So it appears not to be a timing issue.
The ECM wouldn't provide any codes at all - not even code 12 - so I bit the bullet and replaced it. The new one does display code 12, but has no other codes set.
For good measure, I replaced the O2 sensor. It was covered in soot.
Still it runs very rich, and won't idle smoothly (stumbles and dies).
I guess I'll take a look at the IAC and throttle body tomorrow. I hope to have something to report.
jr
The ECM wouldn't provide any codes at all - not even code 12 - so I bit the bullet and replaced it. The new one does display code 12, but has no other codes set.
For good measure, I replaced the O2 sensor. It was covered in soot.
Still it runs very rich, and won't idle smoothly (stumbles and dies).
I guess I'll take a look at the IAC and throttle body tomorrow. I hope to have something to report.
jr
Thread Starter
Intermediate
Joined: Mar 2009
Posts: 46
Likes: 0
From: Berwick Pennsylvania
Fuel pressure was tested and was OK. 41psi at turn-on and 38-42 during operation.
I cleaned the throttle body and IAC valve today. It yielded the most improvement yet. Car now idles smoothly at 600-700 rpm and has better response. Still running rich though. I refilled the gas tank and reset the mpg computer. Drove a little around town and out through the boonies. Getting about 16 mpg so far, but mostly stop and go.
I need to get it inspected and take it for a longer run on the Interstate. There is a little stumble on acceleration. It just seems like it's not quite there yet.
jr
I cleaned the throttle body and IAC valve today. It yielded the most improvement yet.
Car now idles smoothly at 600-700 rpm and has better response. Still running rich though. I refilled the gas tank and reset the mpg computer. Drove a little around town and out through the boonies. Getting about 16 mpg so far, but mostly stop and go.I need to get it inspected and take it for a longer run on the Interstate. There is a little stumble on acceleration. It just seems like it's not quite there yet.
jr
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
After all you have gone through I would take a look at the plugs to see what there condition is, I would also recheck the TPS setting, and the timing to verified all was OK. Seeing as there is a little stumble on acceleration.
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,279
From: Hartford WI
Team Owner
Joined: Jul 2004
Posts: 28,430
Likes: 3,279
From: Hartford WI
Have you reset the IAC yet? If you have a scanner, set it so that it is at 15 counts, give or take say 5 counts when the engine is in closed loop and warmed up. After that, adjust your TPS. When you are done, shut down and turn key to "Run" position. DO NOT CRANK. Use the scanner and see what the TPS voltage is at "idle". SLOWLY depress the gas and watch the TPS voltage. You want to see it rise smoothly. If not, replace TPS.
