new to the rb20...need some help getting it to run right

[XOsilvia]

okay guys, bought a 89 s13 with an rb20det, installed by a reputable shop in northern PA that i have seen very good work out of. Car has sat and only been run occasionally since the swap for about 9 months

Mods:Big front mount,6-puck clutch,Shi**y Pacesetter 2.5 inch cat-back (better than stock and i didn't pick for it to be on there)

Problems:Semi-hard start,Barely idles if at all,Revs fine at quarter throttle but anything more results in hesitation/cutting out that sounds like a fuel cut. It will rev freely at quarter throttle but any more gas makes it bog, pop, and sound like its going to die if you dont let off,In nuetral, with no load, it is fine, but as soon as you try to go anywhere and the turbo spools, after about a minute, it blows a hole in the rubber coupler between the compressor and the hot pipe. (have been through three so far)

I know i need a blow off valve to keep it from blowing that hole, that is going on tomorrow, but the question is, will that solve that fuel cut type symptom? Could the spiking boost cause the MAP sensor to see too much pressure and cut my fuel?

Any ideas?? Thanks very much guys, all help apreciated, just want to get this beast running right

[uber95]

What is the fuel pressure? Was the pump changed out when the swap was done?

[XOsilvia]

DOHC KA fuel pump, is an upgrade to walboro absolutely necessary?

[nizmo zilvia]

DOHC KA fuel pump, is an upgrade to walboro absolutely necessary?

Ya!

And what kinda couplers you been using????? It shouldn't blow it up unless its a cheap rubber which is NOT a silicone! I paid $50/ coupler and couldn't be more satisfied with them.

EDIT: http://forums.racebread.com/index.php?topic=636.0 Check that link out!!! DO IT!!!

[XOsilvia]

Well i put a turbo xs rfl on and that fixed the hose part, the 255 is going on in a few hours, hopefully that'll get it running right...

[Yellow4g63]

Ok at times like this I wonder how people drive there cars with any little problem. Why don't you start be checkig your ECU codes to give a idea where to start. Sounds like you have boost leaks, and if you have been boosting on the KA pump for 9 months then you prob fried your pistons. The hard starting is no doubt the cold start signal wire is not spliced into the ecu loom.

[XOsilvia]

the car has been started like eight times on the ka pump, the 255 did not fix the problem. i'm being told vaccume leak or maf....ideas?

[Yellow4g63]

Unplug the maf since your running a stock computer. It will revert to a limp program you won't be able to rev over 3k but it will start and idle.

[craz4240]

Does sound like a bad MAFS.With myt expierience with nissan mafs the car actually idles better with a bad mafs unplugged.Start the car up and pull the plug out from the MAFS if it idles better you have a MAFS issue very potentially.Another thing is the cold start wire....it's pin 43 on the ecu.All I did with mine was for security purpose is wire a toggle switch to the cold start wire...when i want to cold start I flip the switch and fire it up.

[XOsilvia]

i unplugged it, it idles the same and has the rev limiter at 3k...i'm thinking vacume leak or spark problems? any other ideas?

[Yellow4g63]

i unplugged it, it idles the same and has the rev limiter at 3k...i'm thinking vacume leak or spark problems? any other ideas?

Ok now where getting some where. If the car still idleas like crap with the maf unpluged you can rule out vacume leak. It's on a set map with the maf pluged out and should still idle like normal. Have you checked the codes at the ecu? count the flashing red light?

[XOsilvia]

to be honest it kinda idles better with the maf unplugged. i dont think the wiring is done to check the codes, what blinking light? not new to the s13...just the rb20

[Yellow4g63]

It's the same with alot of older nissans. There should be a light on the ecu and the screw you turn to put it into diag mode. You just count the lights off the ecu since they didn't wire up your check engine light.

[AxiOn419]

DOHC KA fuel pump, is an upgrade to walboro absolutely necessary?

Everyone says it is necessary but my rb20 ran with the stock fuel pump for 2+ years until the car was wrecked (no fault of my own). I had no fuel related issues.. Stock boost.

[Yellow4g63]

Everyone says it is necessary but my rb20 ran with the stock fuel pump for 2+ years until the car was wrecked (no fault of my own). I had no fuel related issues.. Stock boost.

What was your A/F ratio at 10psi?