Timing chain guides

[startupboy]

I am looking at a clean 1991 q45 with 160k miles on it.
Can I assume that the guides have been replaced, or is there a way to tell besides the color of the sealant ?
I also think it needs an injector.
I am not sure that I want to take on the project!! I am not a fan of obd1.
Any suggestions ?

[Q451990]

There's no real way to tell other than opening up the cover and checking. The factory RTV sealant on the timing covers was sort of a powder blue color. An injector problem is very likely. Check out http://www.q45.org for the article on ohm testing the injectors.

[startupboy]

The car is $ 800.00, and it has been well taken care of, but if I have to do guides, and remove the plenum , it is not so attractive. If the guides have been replaced I would be more exited.
The money is not the issue. It is having another dead car in the yard.
At what mileage would the plastic guides usually fail?
I didn't think there where any still out there with the old plastic guides

[3Q Jay]

one mild investment you could make if you otherwise like the car is to sample 4oz of oil and have it analysed for wear metals (and other).
won't tell you everything, but if high aluminum, then the oil pump chain wearing into the pump would be suspect. this is common though not conclusive proof when the guides are broke (at least the guide for the pump chain).

[startupboy]

I will go back on Saturday, bring a flashlight, and take a closer look, and decide then.
I am in no hurry. There will be other cars out there that might be a better match for me.
You just can't save every car

[white90esex]

The guides really aren't bad. Just make sure you have got the chains lined up right and nothing really can go wrong. It's a lot easier to do if you pull the motor out. Btw

[startupboy]

Well, I bought the the car. There was red sealer around the timing cover.
Now it needs one or two injectors.
Can anybody tell me whats the difference is between a 91, and a 94 injector?

[3Q Jay]

uhhhh the part number?
90-93 phase 1
94+ =phase 2
they do not interchange. unless you do the rail and the harness too---then you can upgrade your 91 to phase 2.

[Q451990]

Congratulations on the new to you Q! The burnt orange colored sealer is what was typically used at the dealerships if they were using factory RTV. As mentioned above, 90-93 had the same injectors, 94-96 were different. The updated style requires a different wiring sub-harness, and a different fuel rail. There is no data to say if the new ones will hold up to the ethanol in the fuel, which is what causes them to fail. We have never figured out why some fail, while some seem immune to the effects of ethanol. I switched mine to the phase 2 style aftermarket injectors by Standard Motor Products. Testing said that they're not as tightly matched as OEM, but probably acceptable. SMP says they'll withstand ethanol, so that was their selling point for me. I've been running them for about 8 years and roughly 10,000 miles.

[qship96]

factory injectors on my 96Q {phase 2} had no problems with ethanol fuel nor the mtbe crap used before that,all 315,000 miles they drank that crap and were never removed from the engine nor "bg cleaned" or other such nonsense they push these days.....an occasional bottle of injector cleaner tossed in the fuel tank is the only "service" they ever received.A lot of owners fall for a lot of unnecessary "services" that were frequently pushed years ago on this forum by the vocal minority,none of whom were actually trained automotive technicians,nor automotive engineers.They had people thinking the world was goi8ng to end with ethanol fuel.

[maxnix]

A neighbor had a 1992 with close to 200K and as far as we could tell, not valve guide replacement.

The key, (if there was one) in his case was frequent oil changes. Old oil seems death for sure for the all plastic guides, but not certain if fresh oil will save them either.

I recall in the distant past seeing a metal reinforced guide fail too with a fracture. Just keep the oil fresh.

[Q451990]

As far as I know, there was only one report of a metal guide failure. It was at T3, where the plastic cover on the metal backed guide came dislodged from the metal portion. I had guide failure on my first Q with documented good oil change history.