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1988 Pickup SPX

Couple questions, hopefully someone out there knows for sure. Subject vehicle is a 1988 Mighty-Max SPX, 2.6l manual transmission, federal emissions.

I've been having some carburetor problems, I've had the thing overhauled, and while things are better they still aren't quite right. When accelerating at full throttle it seems to take off okay, and I can feel the secondary open up as RPM's increase. The secondary vacuum chamber is new and it does hold vacuum. If I hold the thing in gear at full throttle at say 4000 rpm and reduce the throttle input too quickly the whole truck will 'buck' briefly, almost as though it was loaded up and suddenly it cleared out. It did not do this up until it failed emissions and I had the carburetor overhauled.

Second issue, which may be related to the first. The fuel pump on this model has three ports, fuel line in from the tank, and two lines out to the carburetor. Does it matter which outlet goes to which port on the carburetor? The fuel pump was leaking and was replaced, and I don't know if perhaps the lines were switched, causing a case of overfueling.

Finally...the underhood diagram of the vacuum lines is nearly impossible to decipher, and the haynes manual is completely useless in this regard. Does anyone have a factory vacuum diagram for this vehicle that they could email to me?

Thanks for any help.

Chris

Reply to
Hal
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There are a bunch of folks there that have the 2.6l engines. Do you have the factory Minuki (sp?) carb or an aftermarket Weber carb? The factory carb has a few weak points. When it's operating it's a good carb. They should be able to help you with the fuel lines and vacuum lines.

Reply to
MG

It is the factory Mikuni-Solex carburetor, model 32-35 DIDEF. Finding a rebuild kit for this model is nearly impossible. I had it overhauled by a place in phoenix (Carburetor Exchange) with a lifetime warranty but it's acting about the same as before, slightly better but not nearly as good as when it was rebuilt in 1996, that one ran flawlessly for almost

8 years.....

The truck is getting a new engine tomorrow(144k, guides and rings are shot) so if it's still not quite right after that I'll see if I can troubleshoot it some more myself before I go back to the shop. I already found what looks like a accurate diagram for my truck, so thanks for the link. I'll keep everyone posted on the progress.

Chris

Reply to
Hal

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