97 fuel injection problem

Phillip Cross · 09-08-2005, 10:55 AM

Just learned that the fuel injection system is leaking on my 97. Researched prior postr and read info by BlazerLT and others on cpi unit/nut kit replacement, also article by Linder Tech from BlazerLT post.

My question is about updates for a 97 system. The Linder article says that individual components can be replaced on a 97, where this was not possible with the unit used in the 95s. Does this mean anything for the repiar on a 97? Or is the entire unit ususally replaced once a leak is detected.

The tech who has my car now is runnig a fuel system cleaning and will retest fuel pressure, but has also warned that an entire unit replacement may be necessary.

BlazerLT · 09-08-2005, 12:08 PM

Quote:

Originally Posted by Phillip Cross

Just learned that the fuel injection system is leaking on my 97. Researched prior postr and read info by BlazerLT and others on cpi unit/nut kit replacement, also article by Linder Tech from BlazerLT post.

My question is about updates for a 97 system. The Linder article says that individual components can be replaced on a 97, where this was not possible with the unit used in the 95s. Does this mean anything for the repiar on a 97? Or is the entire unit ususally replaced once a leak is detected.

The tech who has my car now is runnig a fuel system cleaning and will retest fuel pressure, but has also warned that an entire unit replacement may be necessary.

You might be being scammed.

You can replace separate components on a 1997. Complete replacement is NOT necessary and dont' listen to them.

If the fuel pressure is not rising, you need to have the fuel filter replaced and the fuel pressure regulator replaced on the fuel injection assembly.

Ask him why he thinks the whole thing needs replacing. Let's see what bullshit he tries to throw your way.

GMMerlin · 09-08-2005, 12:20 PM

Your mechanic is probably not using the proper procedure to clean your injectors.
There is a GM TSB in regards to the CSFI fuel system that engine uses.
The injectors on that engine are a poppet type design, contaminants in the fuel along with hydrocarbon build up inside the engine will cause the ball will stick in the seat.
THE ONLY WAY to unstick the poppets is with high pressure nitrogen, and then clean them with a 10% solution of TEC and gas.
If the poppets will not unstick, there is a new updated MFI conversion kit available from GM that will eliminate the problems due to the poppet type system.
The conversion kit comes with a complete meter body and new style injectors.

BlazerLT · 09-08-2005, 12:43 PM

Quote:

Originally Posted by GMMerlin

Your mechanic is probably not using the proper procedure to clean your injectors.
There is a GM TSB in regards to the CSFI fuel system that engine uses.
The injectors on that engine are a poppet type design, contaminants in the fuel along with hydrocarbon build up inside the engine will cause the ball will stick in the seat.
THE ONLY WAY to unstick the poppets is with high pressure nitrogen, and then clean them with a 10% solution of TEC and gas.
If the poppets will not unstick, there is a new updated MFI conversion kit available from GM that will eliminate the problems due to the poppet type system.
The conversion kit comes with a complete meter body and new style injectors.

Worse case snario he isn't going to need 6 whole new injectors, the ECM will pinpoint which are not opening properly with a misfire.

If he is just in need of a cleaning, it will fix it. If he needs one or more injector, he can replace those, but he doesn't need to replace the whole system.

That is a scam.

Phillip Cross · 09-08-2005, 01:39 PM

Quote:

Originally Posted by BlazerLT

Worse case snario he isn't going to need 6 whole new injectors, the ECM will pinpoint which are not opening properly with a misfire.

If he is just in need of a cleaning, it will fix it. If he needs one or more injector, he can replace those, but he doesn't need to replace the whole system.

That is a scam.

Thanks guys for the quick reply. All the tech said so far is that the fuel pressure is 60 intially and then falls to zero. He is not absolutlely positive that that it is not the fuel pump, but that he pinched the return line and the pressure still drops. This along with the run rich codes he got form the cocmputer leads him to the injection system. He is going to run a cleaning service and advise(I will check about the service bulletin and the high pressure procedure noted above) I will suggest that he test to determine which injectors are leaking and will post his reply to this info. thanks again.

Phillip Cross · 09-08-2005, 02:06 PM

Quote:

Originally Posted by Phillip Cross

Thanks guys for the quick reply. All the tech said so far is that the fuel pressure is 60 intially and then falls to zero. He is not absolutlely positive that that it is not the fuel pump, but that he pinched the return line and the pressure still drops. This along with the run rich codes he got form the cocmputer leads him to the injection system. He is going to run a cleaning service and advise(I will check about the service bulletin and the high pressure procedure noted above) I will suggest that he test to determine which injectors are leaking and will post his reply to this info. thanks again.

Here is a link to a bulletin about injector upgrades. I think it means that that chevy recommends conversion to a new style injector, but that upgrade requires replacment of entire unit. Iam still waiing for a call back from the tech who has my 97. I will let him talk to see whether he is trying to sell me a conversion or a redo with original parts.

Phillip Cross · 09-08-2005, 02:07 PM

Quote:

Originally Posted by Phillip Cross

Thanks guys for the quick reply. All the tech said so far is that the fuel pressure is 60 intially and then falls to zero. He is not absolutlely positive that that it is not the fuel pump, but that he pinched the return line and the pressure still drops. This along with the run rich codes he got form the cocmputer leads him to the injection system. He is going to run a cleaning service and advise(I will check about the service bulletin and the high pressure procedure noted above) I will suggest that he test to determine which injectors are leaking and will post his reply to this info. thanks again.

Here is a link to a bulletin about injector upgrades. I think it means that that chevy recommends conversion to a new style injector, but that upgrade requires replacment of entire unit. Iam still waiing for a call back from the tech who has my 97. I will let him talk to see whether he is trying to sell me a conversion or a redo with original parts.

http://forums.s-series.org/viewtopic...b7a1cf7ba00e5d

Phillip Cross · 09-08-2005, 03:11 PM

Tech says he was surprised to learn that GM has a relativley affordable update kit that replaces all of the poppets with new units. . I think he said that the parts including gaskets and supplies are 350. He estim,ate 2 hours labor. The dealer wanted nearly 400 to bring it in and do the special high pressure cleaning process which he wowuld not gurantee would fix the problem. the only istake I made was to OK the $150 BG fuel system cleaning which did not work.

BlazerLT · 09-08-2005, 04:11 PM

It could be the fuel pressure regulator.

Don't replace the whole thing that quick.

Do some research.

blazee · 09-08-2005, 06:32 PM

Here a link to a thread that I made about 96+ fuel systems, at the bottom is a link to the complete 14 page TSB:
http://www.automotiveforums.com/vbul...d.php?t=450484

The cleaning procedure is pretty useless for most people. It is almost as expensive as a new assembly. ($150) The new MFI system costs less than $200, if you get it from www.GmPartsDirect.com.

Most of the time, you will not get a code when the poppets are clogged or sticking, and if you do, it will most likely be a P0300 (which will not lead you to the problematic injector and poppet.)

The price for replacement injectors is around $50 each. Which means that it is usually better to just replace the entire assmebly with the updated MFI and fix the problem for good.

If the poppets are partially clogged, Techron injector cleaner will do a good job of restoring them, it is almost identical to the formula that the dealer sells. (they are both made by chevron). Techron can only clean where it can flow, so if the poppet is completely clogged it will have to be cleaned as outlined in the TSB or replaced.

GMMerlin · 09-08-2005, 06:49 PM

Quote:

Originally Posted by Phillip Cross

Thanks guys for the quick reply. All the tech said so far is that the fuel pressure is 60 intially and then falls to zero. He is not absolutlely positive that that it is not the fuel pump, but that he pinched the return line and the pressure still drops. This along with the run rich codes he got form the cocmputer leads him to the injection system. He is going to run a cleaning service and advise(I will check about the service bulletin and the high pressure procedure noted above) I will suggest that he test to determine which injectors are leaking and will post his reply to this info. thanks again.

One of the problems with trying to help people on the net is the fact that you get bits of information at a time.
From what you state, I would check why pressure is being lost.
Pressurizing the system and pinching off the return line is half the test..he needs to pressurize the system and pinch off the presure line when pressure has been reached then check for bleed down..if the pressure bleeds down, its a stuck injector or the regulator is leaking internally (From experiance I would say the regulator)
With the rich codes he is getting, this is what it sounds like to me.

Phillip Cross · 09-09-2005, 09:43 AM

[quote=blazee]Here a link to a thread that I made about 96+ fuel systems, at the bottom is a link to the complete 14 page TSB:
http://www.automotiveforums.com/vbul...d.php?t=450484

The cleaning procedure is pretty useless for most people. It is almost as expensive as a new assembly. ($150) The new MFI system costs less than $200, if you get it from www.GmPartsDirect.com.

Thank you sir for the TSB and other info. The new unit is being installed today. One thing the tech said that i did not understand was that when he removed the plenum (upper intake) in preparation for the work to be done this morining there were signs of "leaks on top" and this tells him that a cleaning would not have remedied the problem. I did not ask him to explain as I already decided to go ahead with the update and have some considerable investment in diagnosis already. udging form the other posts here the last issue I guess is whether the fuel regulator was really the culprit. I suppose I will see when the job is done. Thanks again everyone.

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