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'93 Sunbird 2.0L MFI

Hey all,

The car ran out of gas last week (not a smart move, but it happened). Filled the tank, dropped in a bottle of Techron and it ran fine for two days before deciding not to start. I replaced the fuel filter and checked the pump, which hums nicely when you turn the ignition on, but it still won't turn over. My good friend Chilton and I pulled the rail and injectors and turned the key again, showing obviously good pressure up to the rail (gas shot out of the inlet line). I reattached the inlet line to the rail and keyed the ignition again... no spew from the injectors. I figure that leaves one of two problems:

1) The injectors are clogged and need cleaning or replacement (4 x $70 + labor). 2) The injectors aren't getting the signal to inject from the computer.

I have a good friend who's a mechanic and I'll be dragging the car (detatched rail and all) into his shop over the weekend so he can diagnose and ultimately fix it (Isabel permitting), but I wanted to throw this out here to see what the resident experts think. No ned to use layman's terms, I'll follow the tech-speak.

Thanks for replies and I'll reply to this thread when it's fixed to let you know what the problem was. I'll keep an eye on the thread until then in case you want any further info. Thanks again.

Reply to
Frank Dwyer
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You're dead right, it'll either be injector blockage or something going awry in your ECM.

Whipped an injector out and investigated yet?

Nick.

Reply to
Nick Trounson

Reply to
Frank Dwyer

I'm not sure about Techron but some injector cleaners in the past can damage fuel injectors by melting the insulation around the coil. Ok yeah running out of gas isnt smart but taking the fuel rail off to see if it sprays... Just for future referance there is a schrader valve on the rail. Get a rag next time and try pressing on it, its much safer.

There are 3 things I like using for fuel injection systems. One is the actron fuel injector/harness tester. This will pulse your injectors and check for a pulse from the harness. Its good for doing pressure drop test with a fuel pressure gage to see if your injectors are balanced and working. The fuel pressure gage hooks onto that schrader valve mentioned above. Another nice thing to have is noid lights. They also check the harness for pulses.

Since you probably dont have any of those you can try using a multi meter to do some checking. Disconnect one of your injectors and touch the terminals on the harness then have someone crank it over. You should see voltage jumping, if not your then you're ecm isnt telling them to work. If you are getting voltage check the resistance of your injectors. They should all be high impedance injectors and should give you a reading of about 15ohms.

Dunno what else to suggest at the moment.

Reply to
Bonnevilles R Kewl

Reply to
Frank Dwyer

This myth needs to die.

Fuel does not contact the injector windings in the GM Multec or any other brand fuel injector.

Junk Multecs are usually free for the asking at any GM dealership, slice one open lengthwise with a bandsaw if there's any disbelief.

Reply to
Neil Nelson

Reply to
Bonnevilles R Kewl

Ooops, my mistake.

The injector coil is wound on a plastic bobbin, if that melts, you have problems in addition to the fuel contacting the coil windings. ;-)

So, you gonna market that repair sleeve for the 3800s?

Reply to
Neil Nelson

Yeah also the insulation can crack and cause problems. Thats where checking them with an ohm meter pays off.

I cant really market those sleeves because you make the sleeve match the amount of material you had to remove from the upper. However I wouldnt mind getting all the old upper and lower intakes from dealers to refurbish myself. Heck I could start a core exchange type of program.

Hmmmm...

Reply to
Bonnevilles R Kewl

Yup, and when a few squeak thru, the low amps probe on an O-scope catches 'em.

Given the numbers of 3800s out there that have or are going to have this problem occur, and given the relative cost of parts thru GM, I think if your repair stands the durability test, and offers a significant savings, there will be a hell of a market.

Indeed!

Reply to
Neil Nelson

"Bonnevilles R Kewl" wrote

I think that refurbishing the uppers is a waste of time as there is often more problems then just the one passage that you bushed. Plus, you'll have to market that jig too.

You want uppers and lowers? I'll ship em to you, but it might get expensive. We just throw them away.

By the way, another idea that I have seen.......you extract the pipe from the lower manifold, and then install a stepped pipe that fits into the manifold, but has the smaller diameter cross section that extends up into the plastic upper plenum. This would a simple fix, and you could clean up the old manifolds, install the new pipe, and ship em out.

Ian

Reply to
shiden_kai

I would accept only repairable cores and sleeve them myself.

Right the lower on mine does have a stepped down egr pipe. From what I understand (tell me if i'm wrong) Gm's fix for this is a lower with a smaller egr pipe and the upper i'm guessing is still the same but yet they still melt right? If this is so then my fix is a lot better than gm's fix because not only is the egr pipe smaller but the uppers passage is sleeved with stainless steel and has a larger ID. In order for it to melt the plastic again it would have to heat about a .050" air gap and about .050" of steel before it gets to the JB weld rated at 600 Deg and then the plastic intake. Plus the sleeve actually makes contact directly with the coolant passages so theres some additional help.

How much to ship to Ohio?

Reply to
Bonnevilles R Kewl

"Bonnevilles R Kewl" wrote

I haven't seen the uppers melt with the re-designed lower. So far, anway.

I don't know, but I have a 3800 apart, waiting for the lower intake gasket on Monday. I'll keep all the pieces, put them in a box and weigh it and find out what the cost would be.

Ian

Reply to
shiden_kai

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