rb20det major problems

[sidewayss14]

Just got my rb20 s14 running well kinda.. here we go any input would n be great.

Starts up and dies, will start and idleevery so often but has a very very rough idle, won't rev past 2k rpms sounds likeit hits a rev limiter then dies

Had it running for 15 minutes with brand new plugs and it's running so rich that 4 out of 6 plugs are already extremely black and fills my garage up with so much rich fuel smoke you can't breathe massive exhaust back fire

Plugs in cylinder 1&2 are clean and not firing has spark and fue....l compression test on cylinders 1&2 50psi, 70psi cylinders 3-6 150psi.. don't know why i have such low compression in 2 cylinders

Mods- z32 maf, front facing manifold, fmic, gt2871r, 12 psi,3 inch exhaust, wiring specialties harness,255 fuel pump, stock fuel injectors with a ebay tune chip camewith the swap

Cel code for temp sensor...... any ideasforthe low compression, rough idle and running so rich..Bad engine?

[caliber676]

Use the oil method for compression testing to rule out piston rings and do a leak down to see if your hg or valves are causing it. This is all assuming your timing is set properly.

I would junk the ebay chip..ASAP

Sounds like you got a bad engine that needs a rebuild though from first glance

[nick-nismo]

yup either rings or head damage, and why are people still trusting "out of the box" tunes

for the richness, probably the coolant temp sensor being stuck in safety mode (ie. ecu runs engine rich )

[Voodoo_ChildR32]

Low comp between two cylinders is a tell tale sign of head gasket failure. That would explain the over fueling due to low compression. Pull the head.


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[sidewayss14]

I replaced the headgasket with an oem hg and did arp headstuds when i bought the swap valves and pistons looked fine from what i could see

Should have checked the internals more in depth, timing was spot on with new belt, tensioner and waterpump

[amnash]

double check cam gear timing for sh*ts

[sidewayss14]

Finally spoke with the guy i bought the motor from he swears the motor was 100% perfect when i bought it.. he thinks the rings are stuck to the pistons in cyl 1&2.. thoughts on that.. will be doing a wet test after work tomorrow

[sidewayss14]

update

So got the car running on all 6 cylinders, bad timing and had a bad compression tester

Here is where I'm at, car still wont rev over 2k ish, still running rich, starts right up and idles nice now

I have no clue how to hook up the Iac hoses due to the aftermarket manifold when Iac is hookedcar wont start, unplug iac hose and let it suck in air the car starts right up connect iac hose car dies.. I'm stuck on this I have hooked it up 3 different ways and won't start

Ecu wont show me codes, led stays lit I have turned the knob cw and ccw for 10 mins no diag mode

[Skym]

MAF is probably stuffed or have a wiring problem to MAF (common for wires to be pulled out of plug if pull on loom instead of plug itself or can happen on ECU side plug or wiring problem inbetween the two plugs, sometimes best to run new wiring). Stock ECU uses a default load value so engine can be started and rev limit's engine to around 2500rpm.

If ECU won't show diagnostic codes, then there might be a internal problem with ECU (24 pin EPROM chip has dislodged from mainboard if it's in a 24 pin EPROM socket, as found on chipped ECU's). The result is ECU goes into limp mode. Part of this limp mode is running engine rich and can't access Consult to check for sensor error codes.

I would fix MAF problem and fit Nistune to stock ECU (converts stock ECU to the new way of tuning new car stock ECU's, via Consult plug under dash on drivers side of car, that will need to be wired in on your car) and retune engine on dyno.

Also you have to be careful with those tuned on computer tunes, as they never are correct (actually lose hp vs being tuned on dyno). You need to tune engine on a dyno, as each car is different with mods (brand of parts, etc). If using same brand of parts from same manufacturer (Factory, Mines, etc) the generic ECU tune (ECU tune done with one engine on dyno and copied, used on many cars engines) will work.

[sidewayss14]

Maf appears fine wiring is perfect, new wiring specialties harness

Could the entire ecu be bad or just the ebay chip is bad?

Cannot afford nistune for awhile, if the ebay chip is causing these problems is there any chip i can get to get me driving until i can tune

[Skym]

Revlimiter could be part of the limp mode, not MAF related (I always thought it used the revlimiter at 5000rpm). Basically ECU can engage that rev limiter for many reasons and I know ECU does with MAF when ECU doesn't see the MAF (unplugged, failed, wiring problem).

The EPROM chip might have dislodged from EPROM socket (usually the reason behind why it happens), so need to open ECU and push EPROM chip back into EPROM socket (I gather this is why Mines put glue over chip, to prevent this from happening, but I wouldn't do it). But be aware you are playing with electronics, so need to use correct EPROM chip tool and be grounded via wrist strap with a grounded work bench (to prevent static damage to circuit board, etc that can make ECU fail now or many days, month, years later). Could ask someone who deals with electronics (has the wrist strap, workbench, etc) to check if the EPROM chip is seated correctly in EPROM socket.

I wouldn't use another generic chip. But you probably can get the program taken off current EPROM chip and put on a Nistune board, fit to ECU (if send ECU to Nistune in Australia). Then buy the Nistune tuning software, Consult cable later on (or go to a local Nistune dealer in USA who has the tuning software, Consult cable, etc. There's roughly 17 dealers in USA). You can always replace the tune with stock tune, add injectors, MAF, etc and tune on dyno.

Nistune dealers are mentioned on their website (click on dropdown menu) -

http://www.nistune.com/ordering-distributors.php

So cost of Nistune board + small fee for install, small fee for shipping to and back from Australia. Nistune can check ECU on bench to make sure everything is working. It's not as much as you think (probably less than 300 total). Contact Nistune and ask.

I know you don't want to hear this, but tuning ECU should always be budgeted for, it's not something you can skimp on. It's the difference betweeen engine lasting and failing.

[caliber676]

Until you properly tune the vehicle with nistune, you will always be running off an improper tune.

[mptjimmy]

if your trouble ship ng stick a stock eciu back in, who did the harness wiring for other s14 to rb motor?
the cel code for temp sensor will cause that in sr motors, wrong temp sensor possibly