Nasty Engine Problem

meanS4teen

meanS4teen

Spectator
I've been running 10 lbs for a little over two weeks. All of a sudden when I drive the car it starts to tug back and forth only when I'm off the boost. It was more annoying than anything for a while but now the car is completely turning off on me. It will turn off slowly in idle and the worst is when I'm driving and shuts off. Just yesterday I was making a turn and the engine shut off along with the PS, thank God I was going slow. The tugging motion it's making is like your letting off the gas and jumping on it again, it will do it violently sometimes and other times barely, three four times until I get into boost.

I've tried resetting the ECU. We've checked the spark plugs. And now we've disconnected the boost controller entirely (which ruled out compressing in the hoses) and it still does it. Have any suggestions.

Still haven't checked injectors, but was hoping someone might have had this problem before, in case it's something else.

95' 240SX Red Top SR20DET
AEM Tru Boost
Greddy MSPL FMIC
Walbro 255 Fuel Pump
3" downpipe, testpipe
Stock turbo, manifold, injectors
 
Sounds like a fuel problem, Dont quote me on Boosted cars tho...... when I first got my supra it would fight over 2k RPM, I had to clean out the Fuel pump filter(In tank) then it had no problem. My suggestion try fuel might be starving it.
 
Have you tried swaping MAFS. Checking for Vacuum/Boost leaks?

Does it only happen when not in boost?
 
It seems like I'm running too rich, at least it smells that way. Yes we've checked for vacuum and boost leaks. And yes it only happens when not in boost. I'll check the MAF and the TPS once I get home, thanks.
 
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bump... anyone got any ideas?? now ive come to a point, i cannot find a leak, there is good vaccuum everywhere, the maf seems to be working, and ive tested the bov for a leak.....

heres the new discovery, i think it bogs cause when i give it a load, the inlet takes in air, then when i let go, and the bov and wastegate is suppose to let out air, it doesnt and everything comes out of the turbo inlet/ intake pipe....

my question, since the hose that goes to the stock wastegate and bov are shared and have a good amount of vaccuum (enough to keep to my hand when i cover it) does that mean the wastegate actuator is bad? would this cause my bogging and hesistation?? im not too expierenced with this and xatracing is too far away... lemme know please

btw.. im at my friends house under his name....

Thanks in advance
 
I'm not sure about on stock SR's but I don't think the BOV is supposed to be connected to the wastegate. I think it's supposed to be connected to the intake manifold so that once the throttle plate closes it creates vacuum and opens the valve in the BOV.

Do you have a boost guage? If you do, next time it hesitates, watch the boost, see what is happening. check the TPS and MAF, what are you doing with the throttle while this is happening? My TPS was off, and I was having somewhat the same issue, except I would be at half throttle and my motor would just cut out like I had my foot off the gas.

I agree with everyone else, Check the MAF & TPS, and for vacuum leaks again.
 
give the wastegate and the bov there own seperate vacuum lines and sources!!!!!!!!!!!!
 
So it was just the MAF. The stupid plug wasn't connected all the way! Thanks for all the help, I've learned more than I wanted to about my car over the course of 2 weeks trying to trouble shoot the problem. It runs fine now and were planning on installing the Boost controller again tonight. Cars almost ready for Drift Sessions!
 
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