Hello, I was hesitant, but I just purchased a barely used (less than 3k miles) 3000 GT. First line of order is to change all fluids in the car, perform a 60k service (timing belt, etc), and inspect / replace other rubber parts, etc. Car looks and seems to run perfectly.
…but I’m torn on what to do about plugs, wires, ignition coil, etc? Do you feel those parts should be okay, and only sensitive to mileage wear? …or should they be changed as well? Thanks for your opinion.
Hi Brian
You are not the first to ask this question.
The 60k service makes perfect sense because these items may cause damage to the engine if not replaced. The rest of the parts like plugs etc, will only affect performance if they break down and will not cause damage so why replace them if they are not faulty?
I am especially curious as to why so many people rush to change coil packs for no obvious reason. This is 3 independent, fully sealed parts that rarely brakes down. Even if one brakes, why replace all 3?
Is this something that has been read about on some facebook group and now it is in the bible? Can someone answer this for me because I am truly puzzled. Its a bit like saying that you had a puncture so you buy 4 new tires to prevent another one when all of the original tires were good.
If I recall I remember reading online that when the coil packs fail, they bring down the ecu with it. I think thats why people say that. Though I could be wrong and might be thinking of something else but im pretty sure I read about them destroying the ecu when they fail.
Thanks for the input. I was thinking along the same lines whether it was truly necessary. I would assume the sealed coil pack would not break down over time on its own when not in use. Hmm…
This car sat for several years prior to purchasing so I was also wondering if I should replace any of the fuel system components? …in case they are gummed up?
I also understand these have potentially faulty ECU’s. I don’t believe this one has been replaced at any time. Is this something you wait till it fails, or is it something to have it repaired / replaced as a preventive measure?
Thanks again guys,
Brian
Ecu’s should be serviced in these cars as they are 23-31 years old now. They are well past their electronic expiration date. Electronic expiration refers to things soldered to the circuit board such as capacitors which are probably already starting to leak. Ecu’s sound be services every 15-20 years to be on the safe side, even on low mileage cars. Old capacitors will tend to leak over time weather used or not. Most ecu techs charge around $200 in the U.S. and will offer a service warranty.
As for the fuel system, check all the rubber lines for cracks and replace them. For peace of mind, it won’t cost much to just replace an the rubber lines weather they’re cracked or not. If you disconnect your fuel rail from the injectors, you cloud run an alcohol flush through the pump to clean all the metal tubing before you replace the rubber. You can run it through the fuel pump after removing the pump from the tank. It’s easier to connect a tube from the pump to a gallon of denatured alcohol than it would be to pour it into the tank and siphon it out with the pump. You can take a coffee filter and pump into another container and run the alcohol a several times until any debris coming out stops. Also, if your going through all that trouble, you can drop the tank and inspect it and secure a rag to a rod and wire the inside down. Use acetone in the tank to clean out any gummed up fuel.
You’re thinking of the IAC. When it shorts it can short the driver in the ECU.
The coils are not connected to the ecu directly and would not damage the ecu if they were faulty. The problem with all forums and Facebook groups is that you often have people that post and re-post bad advice and then people waste a fortune on parts that they don’t need. Please don’t make the same mistake. If a coil fails, you will have a missfire on 1 or 2 plugs and that’s it. The same symptoms can also be produced by numerous other components so don’t assume it is a coil that has failed. You definitely do not need to replace all 3 coils because one fails and they do not need to be replaced due to age.
To dig a bit deeper into it, coil packs rarely fail at all. Most of the time they leak from worn rubber insulators and replacement insulators don’t cost very much.
In my truck, cook packs are around $100, but the insulator boots are $15. They’re very easy to replace as the slide over the working end of the pack (the part that connects to the spark plug).
In the case of 3000GT’s though they don’t have insulator boots because they have spark plug wires. People do do coil on plug conversions though and then would have an insulator boot.
If you’re electronically adept, the ECU capacitor kit will run you about $15. I purchased one cap kit for the TCU and the ECU, and (if I recall correctly) the suspension control module as well. I’ve been too hesitant to mess with something that currently works on my '92 SL, but I realize I’m playing with fire by delaying the inevitable.
If you’ve the funds (geez, a GT with 3,000miles… I’m so jealous!), send them in for rebuild. Capacitors DO fail over time.
Good info, thanks very much for the feedback.