mattsrx7

I have recently had a rebuilt engine put back into my 1986 Series 4 by a mechanic. He has basically just done a straight engine swap a 13bt for a 13bt. But the problem now is that when you try to boost the car above about 2 pound the whole engine just shuts down. With my other engine it used to cut the fuel out when you hit 10 pound boost, but this feels and sounds totally different. Once in third, fourth, or fifth gear if you press the accelerator gently down it will eventually boost up to 10 pound and fuel cut. Some 4 or 5 rotary specialists have had a look at it and haven't had any luck finding the problem, so any help would be greatly appreciated as I have now had the car off the road for over 6 months and really miss driving it! Is there something simple we are just over looking or is the problem deeper than that??????

J-Rat

iTrader: (2)

Loose hose connection causing a leak at boost?

mattsrx7

They have already tried that and found it's not the problem.

J-Rat

iTrader: (2)

was it a long block swap? or a short block swap?

I am trying to figure out what condition that boost would cause, that would cause the motor to shut down.

Does the motor start running again when you go below 2 PSI?

mattsrx7

Im pretty sure it's a short block. The motor starts running again as soon as you take your foot off the accelerator.

J-Rat

iTrader: (2)

Unplug the AFM. Try to drive..

I just read a thread that had the same problem. He unplugged the AFM, and it did the same thing.

mattsrx7

Sorry but what is the AFM???

J-Rat

iTrader: (2)

Its the Air Flow Meter. Its a silver box under the air cleaner.

SBi_Owner

do not overlook timing issues...

mattsrx7

Nothing that has been suggested has worked, if I disconnect the AFM the car doesn't run at all and they have already looked at timing issues which isn't the problem.

trainwreck517

iTrader: (1)

Does it just turn off?

If it starts to bog and back fire when getting on boost, could be a boost leak.


If it feels like a fuel cut.. are you sure all injectors are working? Whats the fuel pressure like? Change fuel pump sock filter, and fuel filter and time recenty?

Thats all I can think of.. good luck.

mattsrx7

It doesn't feel like a fuel cut, and we have checked for boost leaks.

spunks

Have you checked the tps?Use the volt meter method!

mattsrx7

Pardon my stupidity but TPS????

spunks

Throttle position sensor,it detects that you are giving it gas and when you are not.Do a search in this section on how to adjust it.Also try pulling the codes from the ecu as well.

mattsrx7

They made sure that was ok before they put the new engine in as they swapped the TPS over from my original engine.

spunks

They still have to be set especially when removed!

RotaryResurrection

iTrader: (8)

Sounds like a bad secondary injector wire, injector, connection, or injector driver (in the ecu).

RXciting

well today i accidentally sliced into my vacume hose going to the vacume/boost sensor and the car would start run fine for about 5 sec and then just stall

maybe your problem is something to do with the boost sensor/wiring/vacume hose??

mattsrx7

I was just talking to my mechanic and they have kind of narrowed it down to an overboost problem, it has the fuel cut defender installed and now they are finding a new boost sensor just in case, I still don't think it feels like a fuel cut though.