NO BOOST after swap

NTRA08

TWINKY
Authorized Seller
Joined
Jun 10, 2008
Messages
530
Location
Conroe, Texas
I just finished putting my motor from my 87 in my 91. The motor ran fine in the 87 but now when I try to boost it cuts out. I used the wiring harness from the 91, ECU, and all the sensors for the 91. I installed the HKS F-CON in the 91 with the right wiring harness and a HKS FCD type-k. Everything has been wired up correctly. I thought if I hooked up the PBs it would run different. It runs like this with or without the PBs. There are no boost leaks, no exhaust leaks, and no oil leaks. The car starts up fine, Idles fine, and everything else until it starts to boost. I have never had this problem. Could somebody help me.
 

monypit

in the shadows
Authorized Seller
Joined
May 7, 2007
Messages
7
Location
new mexico
please explain the "cutting out" more. will it get any positive pressure at all? does it do it in all gears? at what rpm, will the car still achieve redline with out boost? does it rev correctly in a neutral gear?
 

NTRA08

TWINKY
Authorized Seller
Joined
Jun 10, 2008
Messages
530
Location
Conroe, Texas
monypit: The car revs normal in neutral. I can get to about 3k and then it starts to shutter. Thats about when it starts to build boost from a roll. It only does it under load. The car wont achieve boost in any gear. The car will jump from 0 to +1lbs when it tries to boost.

DBN: The boost gauge sits at -20 which is normal for my car. The stock boost gauge reads too. My only codes are 24 and 52. 52 is fixed. Code 24 is air intake temp signal. That might be my problem IDK.
 

radiod

Supramania Contributor
Authorized Seller
Contributor
Joined
Dec 13, 2007
Messages
1,342
Location
Abbotsford, BC
If it's shuddering a lot it's possible it's a miss. Check your plugs and plug wires. Double check all your wiring, never can be too sure about it.
 

NTRA08

TWINKY
Authorized Seller
Joined
Jun 10, 2008
Messages
530
Location
Conroe, Texas
I've already changed the plugs and wires. Those aren't the problem. It shutters when it starts to boost. AFM is checked out too. That isn't the problem either.
 

DBN

FML
Authorized Seller
Joined
Jan 22, 2009
Messages
247
Location
Fairfield, Ca
It sure does sound like a boost leak to me. Just check all your intercooler lines to be sure.
 

hvyman

Dang Dude! No Way Man.
Staff member
Super Moderator
Authorized Seller
Joined
Apr 17, 2007
Messages
12,768
Location
Tokyo,jp
what about your coils and cps?
 

NTRA08

TWINKY
Authorized Seller
Joined
Jun 10, 2008
Messages
530
Location
Conroe, Texas
When I swapped the motor into the 91 I redid all of my pipes. And my intake manifold. No boost leaks here. All three coil packs have been tested and are good. I switched out the cps when I put the motor in. My other one was wired to a 4-pin trailer connector. Redneck huh. I put it in place just like the other one came out. Maybe the internals on the cps are bad. IDK.
 

Nocheez

Probably posts too much
Authorized Seller
Joined
Apr 17, 2005
Messages
271
Location
Charlotte, NC
I had a very similar problem when I forgot to reconnect my TPS after doing some work. Double-check that it's working properly.
 

monypit

in the shadows
Authorized Seller
Joined
May 7, 2007
Messages
7
Location
new mexico
my coils tested fine on the meeter but onder load they were not firing correctly had to replace them. ah yes the joys ofhaving a ton of extra crap laying around to test with.
 

hvyman

Dang Dude! No Way Man.
Staff member
Super Moderator
Authorized Seller
Joined
Apr 17, 2007
Messages
12,768
Location
Tokyo,jp
you have a 24 which is intake air temp so which is located on the afm.....