Noisey spider

[east302]

So the new MPFI assembly worked...or, at least, it is starting now?

I know the fuel pressure spec with ignition on/engine off is 60-66 psi, so you’re good there. I’ve read that the stock poppets open at 40-psi so would guess it’s the same for the MPFI. If you have 52 at the Schrader valve when running, I’d think that is sufficient.

Try spraying some carburetor cleaner around the injector harness where the o-ring sits. It may have a vacuum leak there. Here’s an article on it:

https://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/rough-idle-after-installing-spider-injector-1

A free check would be to remove and clean the idle air control valve on the throttle body.



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[Joe Dirte]

So the new MPFI assembly worked...or, at least, it is starting now?

I know the fuel pressure spec with ignition on/engine off is 60-66 psi, so you’re good there. I’ve read that the stock poppets open at 40-psi so would guess it’s the same for the MPFI. If you have 52 at the Schrader valve when running, I’d think that is sufficient.

Try spraying some carburetor cleaner around the injector harness where the o-ring sits. It may have a vacuum leak there. Here’s an article on it:

https://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/rough-idle-after-installing-spider-injector-1

A free check would be to remove and clean the idle air control valve on the throttle body.



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Ok thanks. I did notice when i worked the throttle by hand it did run great with no poppin. Just at idle bounces horribly. And ya know... Most vacuum at idle. Since people with scanners cant answer phones guess whos gonna show up at their shops

O yeah. I did lube up new spider ring with atf and upper intake with atf before i put it on and had throttle body off so i could reach in n make sure its seated. I know theres posibillity it could still roll but i never had intake apart on this one when the same idle issue happened before.

 

[east302]

Yeah, I’d start with getting the codes pulled and get those resolved.

Some people use beer as currency. Scanners may cost a six or twelve pack depending on your buddies.


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[Joe Dirte]

Beer doesnt even work on these people. Maybe i need get my cute neighbor girl to ask em. Bet theyd all show up then be pissed to see her waitin in my truck haha

 

[454cid]

Try unplugging the MAF and then try starting the truck. Mine would run crappily, throw a code, then decide to ignore the MAF and run better. Maybe your truck isn't quite bad enough for the computer to ignore the MAF.

 

[Joe Dirte]

Try unplugging the MAF and then try starting the truck. Mine would run crappily, throw a code, then decide to ignore the MAF and run better. Maybe your truck isn't quite bad enough for the computer to ignore the MAF.

Tried it. No change. Old boss said try a tps. I got couple spares. Try tmrw see what happens.

 

[Joe Dirte]

Wondering if i might have a fouled plug way its actin now. Gonna pull em after it cools down n check em out. I did remember that when old spider leaked it cleaned the rear half of lower intake and regulator and left some fuel in the runners. Ill start with the rear plugs n go from there.

 

[Joe Dirte]

And there it is. 6000 miles n reekin of fuel. Pulled all 8 and used fine wire wheel to clean em. Reinstall and runnin A LOT smoother. Still a lil shaky but not like before. Next, get the timing set.

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[redfishsc]

Yeah the old spider in my 99 Suburban looked like it was pissing a lot of fuel too. Terrible mileage.

I just put new cylinder heads on it to replace the cracked one, and took the time to upgrade to the MFI injectors and new lifters.

Took me a LOT longer to clean the carbon crap off the pistons than I expected, the old injectors seemed to have really coked them up.

 

[Joe Dirte]

Yeah the old spider in my 99 Suburban looked like it was pissing a lot of fuel too. Terrible mileage.

I just put new cylinder heads on it to replace the cracked one, and took the time to upgrade to the MFI injectors and new lifters.

Took me a LOT longer to clean the carbon crap off the pistons than I expected, the old injectors seemed to have really coked them up.

My intake was caked bad with carbon. I cleaned it up with some purple power and did throttle body while i waited on parts. The mpfi spider is finally quiet now. Im guessin it was needin the air out n thats y it was loud, like when tank is low u can hear the pump lil more.