still looking for help
Thread Starter
Instructor
Joined: Feb 2005
Posts: 125
Likes: 0
From: york pa
still looking for help
I have a 85 L98.This winter here is my list of mods.
1.Egr and emission removal
2.ford 24lb injectors.
3.removed ac and cruise control(I know but i like a clean unclutered engine bay)
4.msd 8.5 wires and new plugs.
5.removed cold start valve.
car starts fine and runs decent fro about 45 seconds after that the car starts to surge and carry on.My rpm's will run from 550 to 910.I've rulled out vacum leaks not sure if i'm overlooking someting or not.
Please help
1.Egr and emission removal
2.ford 24lb injectors.
3.removed ac and cruise control(I know but i like a clean unclutered engine bay)
4.msd 8.5 wires and new plugs.
5.removed cold start valve.
car starts fine and runs decent fro about 45 seconds after that the car starts to surge and carry on.My rpm's will run from 550 to 910.I've rulled out vacum leaks not sure if i'm overlooking someting or not.
Please help
Burning Brakes
Joined: Sep 2000
Posts: 1,199
Likes: 1
From: NewCastle IN. USA
hmm,
well it starts fine when cold (without a cold start injector), and since ford rates their injectors at a lower fuel pressure (36 or 38psi) and your stock injectors were rated at 42psi, I'd say your running rich.
an adjustable fuel pressure regulator might cure things since your not too extreme on mod's. it might crank a bit longer when cold (once you have it dialed in).
the other (and probably better) alternative is to reprogram the computer to work with the new injectors and the absence of EGR/emissions.
both options require scanning software (to make the most of things). but you may be able to get it close with just the AFPR (not sure if the 85 computer will throw codes without the EGR/emissions, it can happen on later models though).
well it starts fine when cold (without a cold start injector), and since ford rates their injectors at a lower fuel pressure (36 or 38psi) and your stock injectors were rated at 42psi, I'd say your running rich.
an adjustable fuel pressure regulator might cure things since your not too extreme on mod's. it might crank a bit longer when cold (once you have it dialed in).
the other (and probably better) alternative is to reprogram the computer to work with the new injectors and the absence of EGR/emissions.
both options require scanning software (to make the most of things). but you may be able to get it close with just the AFPR (not sure if the 85 computer will throw codes without the EGR/emissions, it can happen on later models though).
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
I believe you have it backwards.
The 85 bosch injector is rated at 21.5 @ 36 psi. The same injector puts out 24 lbs @ 43 psi.
The 24# ford unit flows the same as the 21.5# Bosch unit on the 85.
The 85 bosch injector is rated at 21.5 @ 36 psi. The same injector puts out 24 lbs @ 43 psi.
The 24# ford unit flows the same as the 21.5# Bosch unit on the 85.
Burning Brakes
Joined: Sep 2000
Posts: 1,199
Likes: 1
From: NewCastle IN. USA
Originally Posted by CentralCoaster
I believe you have it backwards.
The 85 bosch injector is rated at 21.5 @ 36 psi. The same injector puts out 24 lbs @ 43 psi.
The 24# ford unit flows the same as the 21.5# Bosch unit on the 85.
The 85 bosch injector is rated at 21.5 @ 36 psi. The same injector puts out 24 lbs @ 43 psi.
The 24# ford unit flows the same as the 21.5# Bosch unit on the 85.
I thought the 85 came with a 25lb injector and the 86 and later ones used the 22lb injector? (I could be wrong though).
you can test the power at the injectors (they are hot with the key ON, ECM supplies ground to fire them) using a meter. If you don't have a chiltons manual (or GM) then you should pick one up, its invaluable for troubleshooting on these cars (lots of proceedures for setting things on the ECM controled devices).
Pro
Joined: Sep 2003
Posts: 588
Likes: 8
From: Tampa Fl
I don't have my book on me, but there is 4 modes of operation for the L98 engine: open loop, closed loop, closed loop - PE, and limp home. The car starts in open loop mode and remains there until the car warms up. At that time it switches to closed loop mode when the O2 sensor is used to control the AFR instead of the chips pre-calibrated set. Maybe the O2 sensor went haywire?
