Help! Misfire after Delphi MFI install

[elsamurai]

1999 Yukon

Dropped the truck off this morning to have a new Delphi MFI unit installed to fix a misfire I've been chasing (replaced distributor, plugs, wires, fuel pump so far). He just called and said it's misfiring worse after the install and he's stumped.

Anything obvious he may be missing that I can have him look for?

 

[SunlitComet]

Retrace all the components be touched for damaged components and remove the spider injector harness and see if the terminals got damaged. Be absolutely sure the connector is fully seated that the retention lock go in freely with out binding. Can you say what cylinders are misfiring?

 

[elsamurai]

cylinder 4 misfire. everything traced out fine, compression is great on all cylinders. it looks like the Delphi FJ10566 is not compatible with the Yukon (???). something about a computer mismatch. never heard of that. so i ordered a stock replacement spider (CP50103-8). we'll see if that fixes it.

 

[elsamurai]

Replaced with a rebuilt stock unit, and it's good as new. So for those wondering, the Delphi unit listed for the Tahoe/Suburban is not compatible with the Yukon.

 

[SunlitComet]

not possible. you may have just gotten a damged one. you should not have put the original design back in. the units are compatible with any vortec 350 installed in any chevy/gmc truck suv or van. there is no computer incompatibility in certain vortec 350 pcm in regards to fuel injectors. they use the same colored wires in the same cavity location from 1996-2000. only the vans have different pin out but on the pcm only.

 

[elsamurai]

strange then. not that the amazon database is the be all end all, but i double checked the part number for the delphi unit and it's listed as not compatible.

anyway, got 170k out of the original. if i get 100k out of this, i'll call it good. runs better now than when i got it...i suppose that's the important part.

 

[SunlitComet]

just a glitch in the database. for some reason the delphi unit was left off under your vehicle criteria. yet the delco version is there. and it is the same kind of unit and says yes it will work on applications i mentioned before. sometimes 1999-2000 application guides do these to avoid giving out incorrect part by accident. forces you to call and verify something to be sure. i think you got unlucky thats all.