North American Turbocoupe Organization



CEL while driving but no codes
88TrboBird Offline
Junior Member
#1
Purchased an 88 TC about a month ago and have had a few issues. I'll start off by telling you what i've done.
Set base timing and idle.
Set TPS
Cleaned IAC
Fixed and verified vacuum routing(thanx to this site)
Fixed tear in egr diaphragm(holds vacuum now and no more code)
Checked Fuel pressure(32psi at idle with vacuum, 41 without vacuum). Now the wierd thing i noticed yesterday. Starts at the 32 psi idling when cold. After 15 min of running it was up to 38psi. Have not checked pressure while driving.

What I'm getting is a very slight rough idle(was worse when egr was hooked up wrong) and at cruising rpm around 2200-3000(doesn't matter what speed)I'm getting what feels like a miss. And if i'm trying to enjoy some "spirited driving" between 3500-4000 its starts to buck and fall on its face. Like its running lean or the timing is being backed off.(knock sensor not hooked up).
It appears that the WG is either blocked shut or is stuck shut(can't even move it by hand). Has a BOV wich seems to work fine except for one time the otherday when i was getting on it the intercooler was blown off the throttle body when shifting at roughly 4k rpm. Though I think this was a case of the clamps not being on all the way or tight.
Sorry for the long winded post, just getting frustrated with it. I don't really have any driveability issues while driving normal and im still getting between 22-28 mpg depending on how bad of day I had at work Smile Thanx for any info or help you may be able to give.
1988 Turbo Coupe. 5 spd
BOV and the rest is stock for now Smile
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88TrboBird Offline
Junior Member
#2
Forgot to mention I'm also getting a jumping idle again after fixing the egr and vaccuum line routing. Maybe i should check the tps again. Also when driving normal and i push in the clutch to slow down for a stop sign/light the rpms drop to about 4-500 and almost stalls.
1988 Turbo Coupe. 5 spd
BOV and the rest is stock for now Smile
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Pete D Offline
Posting Freak
#3
Welcome
Quote:Starts at the 32 psi idling when cold. After 15 min of running it was up to 38psi
Check vacuum at the same time. May have a vacuum leak opening up as the engine warms up.

Quote:What I'm getting is a very slight rough idle(was worse when egr was hooked up wrong) and at cruising rpm around 2200-3000(doesn't matter what speed)I'm getting what feels like a miss. And if i'm trying to enjoy some "spirited driving" between 3500-4000 its starts to buck and fall on its face. Like its running lean or the timing is being backed off.(knock sensor not hooked up).
See comment above. Vacuum leak and/or an air leak (IC hoses or VAM hose. Leak or hose off location or not clamped. Remove and thoroughly inspect.

The WGA is suppose to be stiff and is practically unmovable by hand. Apply 10 psi of regulated air supply to the WGA port and see if the rod moves just a few thousandths of an inch.

If you have the stock IC do you have the bracket on the front that mounts to an exhaust manifold bolt? If not you are going to have problems with the IC blowing off.

Your signature says you have a stock 88. They did not come with a BOV. Does it really have a BOV or are we talking something else? If it is really a BOV, you might want to take it out and plug the system until the other issues are resolved. Sometimes idle and rough running issues are due to faulty or improperly set BOV/BPVs

Jumpy idle and almost stalls. See previous comments. Always good to check the TPS and adjust if necessary. You can also clean the IAC. See comments about BOV.
Pete Dunham
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88TrboBird Offline
Junior Member
#4
Yes, Previous owner installed a BOV. Forgot to put it in sig. All fixed now. It does have stock turbo and IC but the bracket is missing apparently( i wondered if thats what the threaded holes were for in the IC) I'll have to get one. Will inspect the air intake system real good for cracks/leaks. How would i go about checking vacuum (sorry for stupid question) just hook up a vacuum gauge to the tree?
Is there anything else that would set a CEL while driving but not store codes?

And I will remove the BOV and see how things go. And double check the TPS again just to make sure it hasn't moved.
1988 Turbo Coupe. 5 spd
BOV and the rest is stock for now Smile
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88TrboBird Offline
Junior Member
#5
Forgot to add. The reason I asked about the WG is because I'm getting full boost (15psi according to stock gauge) even when fuel switch is on regular, wich I thought limited boost to around 10 psi. Wasn't sure if it was the WG or something was done with the switch. Stock boost controler is there and is hooked up like it should be.
1988 Turbo Coupe. 5 spd
BOV and the rest is stock for now Smile
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Pete D Offline
Posting Freak
#6
An early build 88 is programed for 15 psi in 1st and 2nd gears, and 10 psi in the top 3 gears.

A later build 88 is the same in 1 and 2 but will get 15 in the top gears after 4K rpms.

Both of the above assume the stock BCS is working.
If it isn't in the circuit and working, then the fuel switch can't change boost. If the case is cracked, it can leak and not work.
Pete Dunham
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Jeff K Offline
Administrator
#7
Are you sure you ran the KOEO test correctly and didnt exit the test before the CM (continuous memory) codes were outputted? Remember exiting the KOER test during the test will erase any codes present.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
11 Crown Vic Interceptor
14 Toyota Camry (wifes car)
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Pete D Offline
Posting Freak
#8
The other thing is if the orange wire is not attached to the turbo inlet fastener, the EEC won't report codes

Yes, just use a vacuum gauge attached to the vaccum tree or better - T d into the smaller port off the upper intake to the fuel pressure regulator.
Pete Dunham
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88TrboBird Offline
Junior Member
#9
OK, got a chance to do some work on it today. Checked vacuum at tree and at intake port. Both were about 19-20. Found a small vacuum leak at the tree but didn't change anything. So I disconected the BOV and low and behold the idle straightened up tremendously. And upon driving it, the engine no longer wants to stall when I come up to a stop. Seems like the turbo spools up a little quicker also. Is there a way to check the BOV, or are there insctruction somewhere to adjust it?

Thanx for the help, really appreciate it.
1988 Turbo Coupe. 5 spd
BOV and the rest is stock for now Smile
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