SR Bogging when pedal is down, backfiring

[Bryson]

Hey guys... I'm still working to get my SR running properly.

The intercooler piping is all connected and i now have my boost gauge hooked up, but I'm still having problems with the ol' car.

The vacuum lines should all be in use or plugged now, and the intercooler piping shouldn't have leaks... though it may now I'll get to that.

The can idle fine or at least for a minute or so but then it will start to stutter and die.

If I rev it it will sometimes rev freely, other times it will bog when you hit the pedal then rev. The car starts backfiring.

This is all with the car just sitting in neutral.

I've driven it up and down the street twice, each time it runs ok until I actually hit the pedal. Once I do that the car begins to studder and has practically no power, it then starts to backfire like crazy.

The first time I started the car after hooking up the boost gauge it was at -18 psi or vkgm or whatever it was reading in .

thinking that it could have been a boost leak problem my friend and I took all of the piping off and redid it.... now its at -10-13 which I know is low.

Any ideas?? The only thing not hooked up still is the o2 sensor because I'm not exacly sure where the wires all go from the o2 to the harness. and I know it should atleast be driveable without it hooked up... and this is def. not.

[Hijacker]

check your timing. any kind of bogging can be attributed to a misfire, and it's normally the first thing i check when i have bogging issues. 16 degrees BTDC (next to last mark on the crank pulley).

The vacuum should sit at -18 in Hg. Also, run the car at stock boost until you get this issue fixed. Trying to run it at higher boost before the car is running smoothly can compound the difficulty of problem solving

[Bryson]

ok will do. I thought it might be timing, that means I need to get a timing gun though, I set the timing initially to get it started by lining the the thick pin comming off the block above the crank pully with the second line from the left. I also put the CAS in with the middle and bottom lines lined up so that once it went in the Cam gear would cause it to rotate slightly and the bottom and top lines on the CAS would line up. As far as the vacuum thing goes, I think that it was probably air tight before, since it was sitting proeprly at -18 to -20 somewhere in there and now that its like -12 I must have caused a leak when I redid all the piping.

I haven't changed the boost at all yet.

[Movingviolation240]

Sounds like a boost leak or a bad MAF to me.

Will it rev at all past 4000rpm? Try unhooking the MAF and see what changes, ect.

Paul

[Nismo_Freak]

MAF is my bet... check the connector as well, sounds like it could be loose.

[nismostate]

yea, that might be the problem. I would still get a timing gun too. It will be very useful in the long run. Better to know that your timing is right then believe it is. Friend of mine had his factory tape on his and still had the wrong timing. 5 degress off. Make sure it's on the 2nd line from the right.

[Bryson]

Last night I was making brackets for the intercooler so I haven't messed with any of the thigns you've mentioned. I believe it revs past 4k but I have a DOHC tach and still it doesn't show the revs...maybe loose wire out of the 6 dash wires?? I have to replumb the intercooler piping tomorrow then I'll try wha you've said. When I first started it with no intercooler piping installed on the driver's side... it ran WORSE with the MAF unhooked... backfired like mad. Haven't tried since it was properly connected.

I'll let you know how it goes tomorrow, I also think I am going to try to set the timing again, still trying to find a timing gun.. have 3 friends with em and each is pooning out on simply bringing it over for one reason or another.

[Bryson]

Well I rehooked the intercooler piping up and its still reading -12 vacuum as opposed to the -18 it was just a week back before I redid the intercooler piping. I unhooked the MAF and with it unplugged the car can't even idle without dying, you have to constantly give it gas.

Haven't tried to mess with the timing yet... I still think I have a damn boost leak + poor timing.

[cnichols]

Mine did the same thing because of a blown headgasket....checked your compression?

I thought mine was timing at first too.

[Bryson]

my compression is 150 on all 4 without warming the engine up before checking it

[Luke]

Mine's doing the same thing after the first start. It's running really rich and won't rev past 2500 rpms. It's so rich, fuel comes out my exhaust

I was thinking that it was the MAFS, so I bought a sohc mafs from a junkyard. I didn't clean it off though, and i'm not sure if it was good or not. All my wiring is fine and i've gone over my piping so many times. I hooked my boost gauge up and i'm reading -16. I'm going to try cleaning the mafs and swapping it out again. What else could be wrong?

[Bryson]

dunno , when I first started mine the intercoolper piping wasn't hooked up and it was so rich that the exhaust was BLACK afte rlike 3 minutes. now it doesn't run like that at all. Just bogs and backfires... I'm prety sure its still an intercooler leak and the piping I think my MAF is fine. When /if I get this figured out I'll get back to you.

[nismostate]

man, what do you guys run at like 5th during maybe 50 mph? Im getting like -25! i don't know but it was really weird. mine stays at really low vac at idle. like about 21. sorry for the jack but i have a weird blow off too.. it will blow off like normal but if i just leave my foot off of the gas it'll make a high pitch beep sound. i know it's from the bov but how come it does that? sounds like it's blowing off twice but the second time it's just a loud beep sound.

[Bryson]

I couldn't run it in 5th if i wanted to..

1st gear bogs but is driveable but backfires like a fiend in mid-high RPMs

2nd gear is driveable as long as you don't give it more than like 20% throttle, and it will pop and bog at higher RPM.

3rd gear is completely undriveable it begins to bog and pop as soon as u hit the gas even barely.

[Luke]

My test drives end up in bogging and bucking, it sucks. My BOV will finally be here monday, right now I have the hole in my hotpipe sealed off. I've got to try and clean that sohc mafs and test it

Does anyone have any instructions on testing the MAFS, TPS and O2 sensors for the S13 blacktop? My ecu has no led to check the codes, Jeff @ heavythrottle said they stopped doing the diagnostics on the blacktops.