They say no good deed goes unpunished, and the same applies for when installing new parts on this car.
On the demand of the OBD 2 system, the GTP recently received a brand new IAT sensor, the install was completely painless, taking mere minutes to finish the swap. With the check engine light cleared, I was hopeful we’d seen the end of our recent spate of fuel economy and drive-ability problems.
However, the very next night the car became totally un-drivable. While the Wife was finishing up her work commute, the engine began to stumble, and over last few kilometers home, it took to frantically flashing the CEL.
Since having a check engine light occur so often, we’d used up all of our “freebie” code readings at the dealer, and the service department was getting as sick of seeing the silver Pontiac roll in as we were of owning it. Knowing the dealer was 2 weeks behind schedule and that the vehicle wasn’t really driveable with a flashing CEL, I was left with some decisions to make.
The least expensive course of action was to purchase a code reader, pull the codes myself and make repairs as required. I have been loathe to purchase a OBD 2 code reader until now, because any of the other Ford vehicles I have in the household can easily be serviced with the Diablosport Predators I use for performance tuning. The 1995 GTS is an OBD 1 system and can be read with a simple paperclip jumper, so the GTP would be the only use I have for this somewhat costly tool. Reluctantly, I ran out that evening and obtained a scan tool.
With my $150 code reader in hand I was surprised to learn the #3 Injector circuit was stuck open and reported a “Generic Misfire”. Basically the injector had been stuck at 100% duty cycle under all throttle conditions, essentially flooding the cylinder with fuel. Chances were, this was the source of our poor fuel economy, misfire, and general engine related issues.
Next morning the GTP remained sullenly in the garage awaiting parts and I drove the Wife to and from work. Once parts dealers opened I began to price and source a single replacement injector.
There were two main options, new $255 each from NAPA or a refurbished unit from the same at $50. Checking the dealer for price comparison showed a $130 list for the refurbished injector. The easy choice was made to run with a refurb NAPA piece and return the old injector for our $10 core charge.
If I had the time, I'd have ordered a full set of 6 from ZZ Performance for less than one from the dealership. But seeing as I had to drive the wife to work once already, I elected to hurry up and get it fixed.
I had briefly considered and quickly discarded the idea of using a junkyard part for two reasons; firstly, a used injector may suffer from less than ideal fuel flow issues, and secondly, finding a GTP in the wreckers locally isn’t a very common thing.
So that evening the replacement was installed without issue. I am pleased to note the #3 injector is quite easy to access, if it were on the firewall side of the engine, I’m sure I’d be singing a much different tune. I reset the codes, started the car, and gladly observed smooth running with no return CEL. After a short road test, the on-board trip computer was reporting 31-32 MPG on the highway, quite good considering ambient temperatures and ethanol blended fuel.
I returned the car to daily driver duty and subsequently observed a large increase in fuel economy, regaining nearly 5 MPG in mixed City & Highway driving. So far there have been no new or returning engine related issues. As a footnote, this car has 170,000km’s or about 105,000 miles; I should sit down and write a laundry list of problems and breakages for easy reference.
After doing a recent oil change, next topic might be a discussion about Oil life monitors and my observations on that system.
Read the Entire Living with a Pontiac Series:
Looks Good on Paper:
UPDATE 1 –
UPDATE 2 –
Back in the Grind - Looks Good on Paper & Living with a Pontiac
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