North American Turbocoupe Organization



New from South East Minnesota
DatMantaMan Offline
Junior Member
#1
Hello all! i just bought my first Turbo Coupe about a month ago and its been alot of fun to drive! The car had been sitting for about 6-7 years before I bought it and its had some questionable work done to it. Ive been in the process of fixing some sketchy "repairs" such as butchered/messy wiring jobs, and incorrect hoses used for the power steering (heater hose yikes). This forum has been invaluable in the information Ive been able to use to fix this thing. However there are 2 issues that have been stumping me. I'm not very familiar with this car or motor so I apologize for my ignorance in advance.

The first issue Ive had is with the fuel pump. It does not prime or run at all with the key on. the only way it runs is via a wire hooked to the blower motor fuse and then to the inertia switch connector. This is how the PO had it just to get the car to run. He mentioned that there was an issue with the inertia switch which is why he wired it this way. The pump runs constantly with the key on when wired this way and I would prefer to do things right and fix this properly. Ive read through the Fuel Pump Diagnostic page in the FAQ and followed the steps to test it. I may have missed something but as of now the inertia switch has tested fine, and I "THINK" the relay in the IRCM is ok. What I've discovered is that there is no power coming from the relay to the inertia switch connector with the key on UNLESS I've grounded the brown wire on the EEC Test Connector. So that leads me to believe there is a break between the relay and the connector somewhere. Am I correct? as I said I may have missed something and plan on going through the tests for the IRCM per the instructions in the FAQ page.

2nd issue is a CEL and a stall issue. I've replaced the distributor cap, rotor, wires and spark plugs with new motorcraft ones. My problem is that when I shift into neutral the rpms drop below 1000 and the engine will die most of the time. Sometimes it will catch itself and the rpms will go up and down before it stabilizes at 1000 again. When it does die, it starts right back up just fine. Its more of an issue when I'm slowing down or coming to a stop. I do have a CEL however when the car is just idling it isnt on. It usually only comes on when I start driving. However it does occasionally turn off when I am making boost and the rpms are over 3000, but when the rpms drop below that when I slow down the light comes back on. I have a scanner and ran through the KOEO and KOER procedures to pull codes. This is what I pulled up:
KOEO: 81, 10, 41, 65, 72
KOER: 28, 34, 41
Based on this info it appears I have a lean condition and a problem with the oxygen sensor? a problem with the VAF sensor which is in the VAM? and an issue with the EGR system. The PO told me when I was looking at the car that the EGR system had been deleted so that might explain the EGR code. Could these codes be what is causing my stall issue? I have a new walbro 255, and a kirban fpr set at 40 psi with the vacuum hose off. I get 18-20 of vacuum at idle as well. I appreciate and thank you for any help in advance!
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firebirdparts Offline
Member
#2
Welcome! I am new too. I had a Mark VII for a long time, but just bought a TC about a year ago.

if the air flow and O2 sensor and fuel curve don't agree, the computer doesn't know which one is wrong. So It sounds to me like you only have one problem indicated by the errors. You might have a separate problem with the idling, but maybe not. Fuel pressure seems right. A vacuum leak might be indicated by the fact that the engine is happier at high load, and of course that would throw off the air flow and o2 readings.

I am new to these cars so i probably shouldn't say much. I have observed that Turbo cars have a lot of leak points between the air meter and the cylinders.
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DatMantaMan Offline
Junior Member
#3
Thanks for your welcome! I've checked for vacuum leaks and haven't found any. I'm going to test the VAM and see if that's working fine. O2 sensor I just replaced. Hopefully I can find the issue
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Jeff K Offline
Administrator
#4
Is the orange O2 sensor ground wire attached to the turbo inlet? If it isnt, the PCM wont get the correct info from the O2 sensor and cause all kinds of problems, including lean codes (code 41).

Is the EGR valve hooked up and functioning (code 34)

Clean and lube the IAC. Is the IAC a Motorcraft part? ALL aftermarket IACs are junk. The only ones that work properly are the Motorcraft units.

Code 72 is a weird one.... possible IRCM or ignition switch issue.
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.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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DatMantaMan Offline
Junior Member
#5
Orange ground wire is attached to the inlet, when I replaced the 02 sensor I noticed one of the pins on the connector was pushed all the way in so it wasn't making a connection with the harness connector.

EGR valve was removed by the previous owner so I'm guessing that's why I'm receiving that code

I did order an aftermarket IAC but will cancel that order and get a proper one if the old one isn't a motorcraft. If it is a motorcraft one I will clean and lube it. I'm also going to check to see if the TPS needs any adjustment or if I need a new one
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DatMantaMan Offline
Junior Member
#6
I adjusted the TPS and IAC was cleaned. Ive yet to take it on a test drive because I'm trying to get the fuel pump to work. It runs with the key in RUN and the brown wire on the EEC connector grounded. However with it not grounded it does NOT run the prime cycle or at all. Where do I go from here? I have another known good working IRCM plugged in and that did not help so that can't be the issue.
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Jeff K Offline
Administrator
#7
Grounding the brown wire in the EEC TEST connector just grounds the pump relay coil in the IRCM to run the pump, The brown wire is in parallel with the pump trigger wire that goes to the PCM. Check the pump trigger circuit from the PCM to the IRCM for continuity, and check the 06 pin PCM connector for damaged / pushed out pins. Ground the PCM connector fuel pump trigger pin with the key in RUN. If pump runs then, and PCM connector and PCM pins look OK, the PCM is not grounding the trigger wire. Pull the PCM cover (4 mm hex bolts if I remember correctly) and look for continuity from the PCM pin to the PCM circuit board.
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.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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DatMantaMan Offline
Junior Member
#8
I ran the car with the hotwire the PO did just so I could drive it. Good news is CEL is gone and no more stall issues when slowing down! Piece of the exhaust manifold gasket fell apart (probably because of 6-7 years of sitting) and I replaced it. There was a small exhaust leak that I hadn't noticed before at the manifold exhaust so that may have been part of my issues with O2 sensor and the lean/rich conditions.

Haven't had a chance to continue looking at the fuel pump issue. Have yet to look at the trigger circuit for PCM to IRCM. Plan to do that soon
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