Cold running HELP!!!
Thread Starter
Heel & Toe
Joined: Oct 2005
Posts: 15
Likes: 0
Cold running HELP!!!
I have an 86 vette with TPI and for the first 15 minutes after you start it, it cannot be driven. It acts and sounds like it is leaning out. I have 40-45 LBS of fuel preasure already replaced the filter and have done the following:
MAF
MAF relays
BCM
PCM
Had fuel system cleaned with a machine
Full tune up
this system has the nineth injector, does anyone know if that pulses while the car is running cold? Or if it just comes on to start then shuts off?
HELLPPP!!!
Thanks
MAF
MAF relays
BCM
PCM
Had fuel system cleaned with a machine
Full tune up
this system has the nineth injector, does anyone know if that pulses while the car is running cold? Or if it just comes on to start then shuts off?
HELLPPP!!!
Thanks
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
Exactly what does, "have done the following:" mean? Replaced? Tested? Looked at? ??? What are the BCM and the PCM especially on an '86 car?
The first thing to do is check for codes that may be set. Trouble shoot and correct all if those. If you still have problems, I would test the ECT sensor.
RACE ON!!!
Originally Posted by zapp168
and have done the following:
MAF
MAF relays
BCM
PCM Thanks
MAF
MAF relays
BCM
PCM Thanks
RACE ON!!!
Thread Starter
Heel & Toe
Joined: Oct 2005
Posts: 15
Likes: 0
I replaced the above mentioned items I replaced the car computer with one from a good running car. replaced the MAF Replaced the burn off relay. THe temp sensor according to the scanner is reading fine there are no codes in the computer. The PCM is Powertrain Control Module.
Thread Starter
Heel & Toe
Joined: Oct 2005
Posts: 15
Likes: 0
As for the injector cleaner I had it done with a motor vac fuel injection cleaning system for $150.00.
After 15 minutes this car runs PERFECT. Spins the tires, chirps second gear.
When the car is cold you try to step on the gas and it sputters and pops from the intake like it is lean. I mean you cannot move the car without it stalling. Again I plugged in a scanner and can watch the temp and it is reading accurate. That was actually the first thing I checked cause it seemed obvious.
Thanks
After 15 minutes this car runs PERFECT. Spins the tires, chirps second gear.
When the car is cold you try to step on the gas and it sputters and pops from the intake like it is lean. I mean you cannot move the car without it stalling. Again I plugged in a scanner and can watch the temp and it is reading accurate. That was actually the first thing I checked cause it seemed obvious.
Thanks
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Burning Brakes
Joined: Feb 2000
Posts: 824
Likes: 2
From: Camden SC
Consider hooking up a scanner and check the short and long term fuel trim figures. I'd check to see when the car goes into closed loop. Does the O2 sensor show rapid voltage moves after about 5 minutes?. Have you ever replaced the O2 sensor? How long has the O2 sensor been in service.
Just speculating.
dlmeyers 90 coupe zf6 3 speed shocks
Just speculating.
dlmeyers 90 coupe zf6 3 speed shocks
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Have you used the Helms to check your cold start valve? there is also a fuse for it. The first step to diagnosis is to attach a fuel pressure gage-then disconnect the distributor 4 way connector-this will disable the other injectors.Engine temp should be below 35C (95F) turn key on for 2 seconds-note gage, crank engine for for 2 seconds while watching the gage (might need help here), if cold start valve is operating properly the gage should drop more than 3 psi.Incidentally, on an 87 the fuse for the cold start is behind warning light display panel-good luck there.Also it is timed to stay on for 8 seconds if operating properly.
Thread Starter
Heel & Toe
Joined: Oct 2005
Posts: 15
Likes: 0
Originally Posted by rick lambert
Have you used the Helms to check your cold start valve? there is also a fuse for it. The first step to diagnosis is to attach a fuel pressure gage-then disconnect the distributor 4 way connector-this will disable the other injectors.Engine temp should be below 35C (95F) turn key on for 2 seconds-note gage, crank engine for for 2 seconds while watching the gage (might need help here), if cold start valve is operating properly the gage should drop more than 3 psi.Incidentally, on an 87 the fuse for the cold start is behind warning light display panel-good luck there.Also it is timed to stay on for 8 seconds if operating properly.
There is a fuse box behind there? or just a fuse? The car has a digital dash.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
On the front of the manifold, next to the ECT sensor, is the fuel injection (9th injector) cold start switch. A Helms would be a big help, here.
A Powertrain Control Module AND an ECM in an '86???
BCM???
RACE ON!!!
A Powertrain Control Module AND an ECM in an '86???
BCM???
RACE ON!!!
Thread Starter
Heel & Toe
Joined: Oct 2005
Posts: 15
Likes: 0
I use PCM and ECM interchangebly, they are both just computers Powertrain control module, Electronic control module, samething really. BCM is body control module. whick controls alot of the electrical controls for the dash and other electronics.
I saw that switch and I am going to move in that direction.
Thanks!!!
I saw that switch and I am going to move in that direction.
Thanks!!!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
Originally Posted by zapp168
I use PCM and ECM interchangebly, they are both just computers Powertrain control module, Electronic control module, samething really...
BCM is body control module. whick controls alot of the electrical controls for the dash and other electronics.
BCM is body control module. whick controls alot of the electrical controls for the dash and other electronics.
RACE ON!!!
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
If it isn't the Cold Start Injector or circuit, a scan can at least verify that the IAC is parked somewhere around 160 (before you start it) and not zeroing out. Unfortunately, with Open Loop operation, there will be no info as to whether it's running rich or lean. You might also try starting it with MAF disconnected.
Might suspect the PROM too - particularly with everything you've all ready replaced. A Bulletin and redesign went into the '85 for a similar problem and should have made it into your Vette. To be sure, you could pull the PROM out, check the # and then make sure it was the latest and greatest for your Year. You should be able to get the # out of the Parts Catalog at www.acdelco.com .
Might suspect the PROM too - particularly with everything you've all ready replaced. A Bulletin and redesign went into the '85 for a similar problem and should have made it into your Vette. To be sure, you could pull the PROM out, check the # and then make sure it was the latest and greatest for your Year. You should be able to get the # out of the Parts Catalog at www.acdelco.com .
Thread Starter
Heel & Toe
Joined: Oct 2005
Posts: 15
Likes: 0
FOLLOW UP:
Testing has revealed that injector nine is not working at all. It has been ordered, but of course is back ordered. I tried using a used one, but it was also sitting for a long time yielding the same result.
Thanks to all who responded, I think when the new part comes in, all should be well.
Testing has revealed that injector nine is not working at all. It has been ordered, but of course is back ordered. I tried using a used one, but it was also sitting for a long time yielding the same result.
Thanks to all who responded, I think when the new part comes in, all should be well.
Burning Brakes
Joined: Nov 2004
Posts: 781
Likes: 0
I thought you can eliminate the 9th injector with no major, adverse affects (like when you install a SuperRam/aftermarket runners)? I would look at the EGR valve or 'slow' oxygen sensor.
Any exhaust mods on this car? Have you run anything other than unleaded fuel through the exhaust (anti-freeze, other chemicals)?
Any exhaust mods on this car? Have you run anything other than unleaded fuel through the exhaust (anti-freeze, other chemicals)?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 32
From: The Top of Utah
Originally Posted by 500hp
I thought you can eliminate the 9th injector with no major, adverse affects (like when you install a SuperRam/aftermarket runners)?
RACE ON!!!
Drifting
Joined: Mar 2005
Posts: 1,923
Likes: 0
From: GA
Originally Posted by zapp168
FOLLOW UP:
Testing has revealed that injector nine is not working at all. It has been ordered, but of course is back ordered. I tried using a used one, but it was also sitting for a long time yielding the same result.
Thanks to all who responded, I think when the new part comes in, all should be well.
Testing has revealed that injector nine is not working at all. It has been ordered, but of course is back ordered. I tried using a used one, but it was also sitting for a long time yielding the same result.
Thanks to all who responded, I think when the new part comes in, all should be well.