77' 280 acceleration problem

[FastWoman]

To be clear, did you still experience a 3000 RPM rev-limit with the TPS unplugged? If you didn't, that *IS* the source of your rev limiting problem. You then would need to verify the TPS is working properly and adjust it correctly.

Edited June 7, 2011 by FastWoman

[brento_1488]

the original problem wasn't so much a "rev limit" it was just more of a not wanting to give any more power because it was running too rich.

[brento_1488]

sometimes when i first start the car it will seem fine and accelerate great for a few seconds then the problem will kick in again.

[FastWoman]

When you first start the car, it's running very rich. Then it gradually leans out as it warms up. You're almost definitely running too lean, rather than too rich. That can give you incomplete combustion and the black, sooty plugs and exhaust that go with it. That can also give you backfire through the intake, as the burn takes a very long time and can extend through the next intake cycle.

To verify that you REALLY DON'T have any intake leaks, try my yogurt cup test. For some reason nobody wants to do it, but one guy on this list would have saved an ENORMOUS amount of diagnostic time if he had simply followed this advice. If it helps you to do it, consider it a "beer can test," although I don't know whether a beer can is really the right size to plug the intake.

You'll need one cup of Yotastic yogurt -- any flavor you like.

[grantf]

See, I told you, can you take a caliper reading on the yogurt cup so I can find the proper beer can? Fastwoman, I will try you're test soon (for another reason), Brento there is no way anyone here can diagnose youre engine trouble, that is why people give different test suggestions, I would listen to both cozye and fastwoman test you're vacuum and you're fuel pressure then continue from there but try the simple things first I have noticed that the efi system on my 77 needs little adjustment but it does need maintenance does this make sense?

[cozye]

fwiw, if it's popping through the intake as you suggested earlier, it's running lean, not rich. Pull the plugs and post a pic of them and that should confirm it.

[cozye]

and if you haven't done so already, order this http://www.summitracing.com/parts/SUM-800160/SuggestedParts/?prefilter=1 and a 3/8 inch T fitting listed in the accessories.

[grantf]

and if you haven't done so already, order this http://www.summitracing.com/parts/SUM-800160/SuggestedParts/?prefilter=1 and a 3/8 inch T fitting listed in the accessories.

or it sounds like a good excuse for me to take a sunny road/boat trip with my Moto Guzzi, girlfriend (Her Ducati) and my fuel gauge to the San Juans!!! Or WTF my car is a 77 also I could race her there, then go scuba diving. Sorry got summer time on my mind.

Edited June 8, 2011 by grantf
spelling

[cozye]

or it sounds like a good excuse for me to take a sunny road/boat trip with my Moto Guzzi, girlfriend (Her Ducati) and my fuel gauge to the San Juans!!! Or WTF my car is a 77 also I could race her there, then go scuba diving. Sorry got summer time on my mind.

I must admit, I am a bit jealous of the great riding you west coast guys have. That's a great excuse!

[FastWoman]

Yeah, road trip!

Grantf, the yogurt cup is tapered, so it fits like a sink stopper. I don't really know/remember where on the yogurt cup taper the thing fits, so I don't know if a beer can would also fit. I guess I'd have to try it. Unfortunately we buy our beer (and softdrinks) in bottles, so I'd actually have to go out and buy a canned beer for that!

[brento_1488]

horay for the yogurt test. fixed an air leak (injector to intake).

so pay day ill order a fuel pressure gauge. im havin a buddy's step dad who was a z machanic come over this weekend.

hopefully that will sort out my $^!#.

i really appriciate the help. this is the most helpful forum ive ever been on

[FastWoman]

Yay! Glad it helped you!