sr20det idles fine, wont drive!

[b145279]

I have an s13 blacktop, all stock including smic. Since install (approx 2 mos ago), starts right up and revs great in neutral. As soon as I put in 1st or reverse and release the clutch, the rpms drop and it bucks/stalls and the gas pedal becomes irelevant to the rpms drop. I have even tried to let out the clutch at up to 3000 rpm and it does not change the outcome. The engine still drops to roughly 500 rpm it dies. I started with all stock items and have systematically replaced with NEW:
AFPR, Fuel Pump, Fuel filters (more than once)
Boost controller, vac lines (vac gauge says vac at 15 @ idle)
temp control sensor, knock sensor
master and slave clutch cylinders and removed damper
brake booster/master.
Timing is 17 btdc
TPS is .43v closed.
FPressure is 40psi w/vacuum
Compr. is 120 across all cylinders
NGK 6's gapped .30
coils are within spec of 1ohm
injectors are within spec of 11.4ohm

I have checked extensively for vacuum leaks, exhaust leaks/obstructions and fuel leaks to no avail.
I am all out of ideas on the problem.
THE QUESTIONS:
Am I overlooking something simple?What?
Could the problem be related to the clutch/trans engagement? It shifts fine, no grind no noise except TOB (I reused the clutch as it looked to be in good condition, throw out bearing is bad though (rattles).
Thank you in advance.

[marquisj74]

I had this problem recently, after a bunch of BS it ended up being the MAF. I unplugged it to see if anything changed, it wasn't making a difference plugged in or unplugged so it obviously was faulty. After I borrowed one for a quick test, It reved to 6k and spit fire, no bog, no rpm die. Not sure if this helps but good luck.

Check the maf.

[OrangeVirus1]

it's probably running way too lean.
engine can idle at crazy lean mixtures and seem fine. but die when you try to drive.

probably maf.

[b145279]

When I unplug the maf the car stalls, for that reason, I assumed that it works, but I will run multimeter on it to verify.
Also, I had tried to increase the fp to 50, but the car seemed to run way to rich, although I didn't try to move the car at that psi, just in neutral. cant hurt to try again.

[OrangeVirus1]

it could be timing, if you are severly retarded on timing, it will idle, but have like zero HP and die if you try to drive it.

Perfect example, In my RB I was idling fine, AFR's good, I pulled 35*'s timing from the entire map and I couldn't get out of my drive way lol

[OnTheChip]

I know this may sound silly, but does the car move when you let out the clutch while in gear?

[b145279]

yes, the car does move.albiet very slowly and choppy, then stalls. My driveway has a 30 degree incline (uphill to the street). I have been testing by moving forward and backward for about 20 feet until incline. Iwas able once to get the car up on the road, and took it about two miles roundtrip to get fuel. It was quite a challange and as you can imagine, sluggish and I was only able to hit about 20/25mph max. I had to baby the gas pedal. I am going to go out to fiddle and test the MAF/CAS and speed sensor shortly and will check back in a bit.
Thanks for the assistance so far.

[OrangeVirus1]

yes, the car does move.albiet very slowly and choppy, then stalls. My driveway has a 30 degree incline (uphill to the street). I have been testing by moving forward and backward for about 20 feet until incline. Iwas able once to get the car up on the road, and took it about two miles roundtrip to get fuel. It was quite a challange and as you can imagine, sluggish and I was only able to hit about 20/25mph max. I had to baby the gas pedal. I am going to go out to fiddle and test the MAF/CAS and speed sensor shortly and will check back in a bit.
Thanks for the assistance so far.

how about just put it in gear and floor it.. see what happens

[nsfmike240]

Your exhaust back pressure may be too much, you can check that with a gauge but if you do not have one then you can just take your o2 sensor out or diss connect down pipe to check, once you do that then drive it around the block, if it is better then you have too much excessive back pressure

[OrangeVirus1]

Your exhaust back pressure may be too much, you can check that with a gauge but if you do not have one then you can just take your o2 sensor out or diss connect down pipe to check, once you do that then drive it around the block, if it is better then you have too much excessive back pressure

the chances of this being the reason, are like the chances of winning the lottery in a state that doesn't sell tickets.

[b145279]

So, I ran MAF tests with voltmeter my idle is 1.8v and @3k rpm 2.6v. The fsm states [email protected] and 1.4-2v @3k rpm is good.
Are my high numbers indicative of a bad MAF? The car still dies if I disconnect the MAF. I cleaned the element with actual MAF sensor cleaner and it looks shiny and new.
Sidenote: when I adjust the iacv screw out (more air,increase idle) the air filter seems to make more of a wind sucking sound. don't know if that is relevant or not.
Also, I have a 3" exhaust with gutted cat, so back pressure shouldn't be an issue but I will check the O2 sensor now, because anything is possible.

[OrangeVirus1]

Sounds like a bad maf, I get like 0.5V at idle. If it was getting higher Volt readings, the engine would run really rich. Running really rich can make it bog, cut out, backfire etc.

the air filter will be sucking more air in because you are adjusting how much air the engine is taking in at idle.

it isn't exhaust back pressure, I'd bet a million bucks on it.

here is what you can do. Disconnect everything and run it on bare minimums.
Injectors, distributor/CAS, spark plugs. See if it starts and what it does. then slowly add each and every outlet until it starts acting up

[cotbu]

the the stock ecu has a low voltage mafs enrichment, and that is .700v if you maf voltage hits that low it will automatically enrich, fix your shit.

Op, check timing? again set it to 15deg, adjust tps to .45v closed, get bkr7e plugs gap .028 adjust fuel pressure to 43.5psi without vacuum.

[b145279]

still working on the disconnecting/reconnecting everything. So far no difference. What happens while trying to backup driveway, I rev the engine to approx 2300 rpm, let out clutch and the car instantly bogs, starts moving then bogs, shakes and dies (exactly like when you don't give enough gas). The problem is that I can push the gas pedal to the floor and it does not make a difference. Ideas?

[ultimateirving]

Sounds like a bad maf, everything that youv'e described sounds like my car when i have blown off couplers on the road, and it takes every ounce of the car's energy to limp to a safe spot. Doesnt want to drive, Bucks and stalls. idles decently but once load is added it struggles.

Get another maf and test it.
Also is the sidemount recirculated? Ive heard them to be faulty and cause issues.

[b145279]

Sounds like a bad maf, everything that youv'e described sounds like my car when i have blown off couplers on the road, and it takes every ounce of the car's energy to limp to a safe spot. Doesnt want to drive, Bucks and stalls. idles decently but once load is added it struggles.

Get another maf and test it.
Also is the sidemount recirculated? Ive heard them to be faulty and cause issues.

I just retimed/adj. fuel pressure and TPS back to orig. recommended numbers. Same issues, but I had my wife try to drive it, and from outside when moving, the SMIC (all stock/recirculated) sounds like carpet dragging on the ground (if that makes sense), like it is struggling. I don't have experience with them, is that normal?

I do not have another maf to test, so I will just buy a new one.
Update. I had a FMIC setup waiting anyway, so I hooked it up. This resulted in zero improvement (except it doesnt sound like a carpet dragging anymore!).

[b145279]

OK. so I decided to time my car via a spark plug wire in the #1 cylinder instead of the "loop" in the back (which I used and have been using, per the fsm). The spark plug wire method showed me that 15deg btdc with the "loop" actually put me at 5 btdc, not where I should have been! Sooooo, I retimed using the spark plug wire timing method and it runs a heck of alot better. A few more minor details to work over and I should be golden.

[OrangeVirus1]

the the stock ecu has a low voltage mafs enrichment, and that is .700v if you maf voltage hits that low it will automatically enrich, fix your shit.

Op, check timing? again set it to 15deg, adjust tps to .45v closed, get bkr7e plugs gap .028 adjust fuel pressure to 43.5psi without vacuum.

I dont have a SR tho

[Rb26kouki]

It can also possibly be engine ground...