89 coupe

[Richard S.]

My 89 coupe has 112,000 miles on the original fuel injectors. I had the car at the dealer yesterday and after testing I was told all injectors needed to be replaced. It seems 5 have low resistance. I was told 89 injectors cannot be cleaned or adjusted and the only option is new injectors. I now have a conflicting opinion from someone I trust. Could someone with more experience than me please offer an opinion. Up here in OH CANADA new injectors are $200,each...nuts eh....
While I'm here can someone also give me a recommendation for new spark plug wires.
Thanks for the help and have a great weekend.

[Joe L.]

Re: 89 coupe

Rick-----

1) The injectors with low resistance will have to be replaced. No matter what you do as far as cleaning it's not going to change that;

2) Even if you could clean and re-use the other 3, would you really want to use 5 new injectors and 3 old ones?

3) If you clean the 3 "serviceable" ones, I don't think that you'll be able to do it effectively and I don't think that you'll be happy with the results;

4) 1989 was the first year for the use of the "Multec", GM-manufactured fuel injectors. However, the same injectors were then used through 1991. These injectors are GM #17112285 and they do GM list for about $145/each US (which should be about $200 CDN). You can obtain them for a lot through Delco dealers like The Last Detail in Atlanta, GA------likely about $90/each US. It's still expensive when you consider that you need 8, but it's a lot less than GM list that most dealers will charge. The AC-Delco part number is 217-292.

Be thankful that you don't have a ZR1 (LT5 engine). Then, you'd need SIXTEEN injectors.

[Richard S.]

Re: 89 coupe

Thanks Joe......I'm thankful......I see Mid America sells a set of 8 for $60.each, US dollars....In your opinion would these be just as good as the GM replacement injectors?
Should I upgrade the spark plug wires or go with the Delco?
Thanks.

[Joe L.]

Re: 89 coupe

Rick------

I don't know anything about the Mid America replacements. If they're a name-brand replacement (like Bosch or Lucas) and they're the correct piece for 89-91, I think that they would be fine. If they're some sort of "reconditioned" piece, I wouldn't use them.

For plug wires, I think that the Delco replacements are going to be as good for you as anything else.

[Richard S.]

Thanks for your help. *NM*

[Chuck S.]

Re: 89 coupe

Rick, was your car running badly and you took it in to find the problem? Or, did you take in some other service?

The reason I ask is that I am inherently distrustful of people that have a vested interest in doing work on cars brought in for service. The name of the game is "Run Up The Tab". Unless the car is running badly, I wouldn't replace the injectors, i.e "if it ain't broke, don't fix it". Injectors are easy to check and easy to change, making them a prime scoring opportunity. Try some injector cleaner first; it may not fix it, but for a few bucks, it's worth a try.

Mid-America sells some C4 parts cheaper than dealers...some of the parts are generic, and some are GM, but I doubt that they can sell new genuine GM injectors for 1/25 the Chevy dealer price. Their injectors may be rebuilt or they may be new private-branded injectors by a reputable manufacturer. If it were me, it would be worth a try before I forked over $1600 (Canadian, I presume) for dealer stuff. Cheap wheel bearings, now, I probably would shy away from...they may be foreign and inferior. JMHO

[Richard S.]

Re: 89 coupe

Chuck, thank you for your comments. I too know and distrust the dealership interest in just changing parts when it's an option but not completely necessary. The car was idleing a little rough but still ran well on the highway. It was also running a little rich but we corrected that problem. Use of injector cleaner did not change anything so when the idle continued to be rough I took it in to the dealer and left them with instructions to clean the injectors, the injector filters and check the injector O-rings. When they called with the news and the cost to replace all the injectors I took the car away from them. Unless someone advises me against it I think I'll try the Mid America injectors. I now see that Mid America, on page 4-26, offers a rotary disk design for $60. each, ($480 for or an Accel injector for $299.for 8 or about $38.each. I don't really know what the difference would be. Thanks again for your help.

[Chuck S.]

Re: 89 coupe

Rick, if the car idles rough all the time, i.e. cold or hot, I would remove the throttle body, disassemble, and clean it thoroughly by manual scrubbing (none of the lazy spray-it-in stuff). Rebuild it with new gaskets, and be sure to replace the idle air valve when you reassemble. L98 throttle bodies are susceptical to carboning or sooting up from PCV vapors introduced behind(?) the throttle plate.

If your car idles rough ONLY when it is hot, there may be a problem with the emissions canister, related hoses and vacuum operated valves (LH front on the frame rail). I believe the emission system continues to purge the canister after it should shut-off or something. If you have a gasoline smell under the hood at the end of a hot run, then that's probably the problem.

If you haven't changed the O2 sensor within the last 50K miles (LH exhaust pipe below the manifold), it probably needs changing as well. If it has never been removed, it will be hard to get out, so be careful not to break anything. You can use a little high-temperature antiseize to make it easier to replace next time, but use it sparingly and DO NOT allow it to get on the business end that protrudes into the exhaust pipe. Metallic contamination will kill the sensor.

Also, if you don't have the GM service manual, I recommend getting one...it is essential for trying to trouble-shoot the late models and it will pay for itself pretty quickly.

[Richard S.]

Re: 89 coupe

Chuck, I've had the service manual since I bought the car in 1989. The throttle body was off and cleaned at the end of last year. It's ideling rough cold or hot. The O2 sensor was changed last year. No gasoline smell ever. I really appreciate your help and advice.

[Chuck S.]

Don't Forget Idle Air Valve... *NM*

[Joe C.]

I've Been Following You And Chuck.................

.........in this thread, and Chuck hit all the marks. There is only one more thing I would do before replacing the injectors. Verify that the resistance is, in fact, low on 5 like the dearlership said. If they test bad, then of course, its a no- brainer. With 100K plus on the clock, it is entirely reasonable that the squirters are tired.

Joe