Starting issues, anybody?

[driftjunke]

Alright, maybe somebody else has run into this when swapping in a S1 RB25 into a S13. Little info on the car, swap was done by another shop, left plenty of bare wire, didn't connect any gauges, no fans, half assed all the way. Anyways car was brought to our shop not running, apparently overheated, blew the headgasket, burnt up the oil and continued to drive needless to say the engine was dead, and wouldn't fire just turnover. We rebuilt the motor, reinstalled it using a new harness, previous was thrashed, and wired it up ourselves. Motor was originally an auto but converted to 5spd, but had a manual harness, which we swapped out due to its condition and used an auto 25 harness. Now the issues is, we get air, fuel, and spark, its just it turnsover for about 30 seconds trying to catch and fire up, takes a couple off tries, still stock fuel system with walbro. I swapped out CAS and the ignitor chip, and it cranks a little easier, sometimes. You can smell the gas when trying to crank and it eventually cranks up. Sometimes though it will fire up first try, cranked everytime about 15 times in a row, let it sit for an hour and no fire up, just turns over trying to catch.

It seems sporadic the ways it acts, any ideas anyone? Checked about everything i could think of, still no luck.

Thanks

E

[driftjunke]

Cranked up first try today, then 10 times after easily, checked every sensor, still same result as yesterday. Maybe it just didn'tfeel like starting easily yesterday. Runs great, I'll post numbers later.



E

[Valley]

you have fuel and spark? has to be compression or timing.

very nice looking engine

[klh6686]

maybe you had some old and nasty fuel in the lines/half the tank? i've had it happen before lol

[vg33t]

Starting issues? Yes, my rb20 has them. First 10 tries it wont fire at all but you can small gas. Then it will start to fire 4 or 5 times every time you crank it sounds like its gonna start for a half a second them dies. Then after about 20 or 30 tries it finally starts and runs like crap for about 5 minutes. After it warms up it runs ok.

[USMCgetsome]

ok had similar problems when i started my rb25det project.

1st - fuel problems. (fuel filter, cleaned injectors,used noid light to verify ecu pluses signal.)2nd - timing belt slipped 1 tooth on exhaust cam caused delayed start and motor ran like total crap. just one tooth caused it to act up horribly.

If you have fuel, spark, air. Has to be timing. i'm sure the ecu is ok. If you guys need more help you can get me at [email protected] this forum helped get my rb25det up and running so i'm always here to return the favor.

[eh?]

Is the start signal getting power?

[driftjunke]

Bad battery or alternator, only reading 12.6 volts on the SAFC2, fires up fine when jumped. Thanks for your help guys.

E

[vg33t]

I bought a new battery today but that did not solve the problem. Still does the same thing. When I crank it fires a few times then it stops firing. I checked the coils for spark and they were good. I checked the cam timing and it was right. I have power at the injectors also. This makes no since, its like something has to warm up first or it wont run. Every time I crank it fires and dies over and over until it starts to fire a little more than I know its about to start. I have to give it throttle to get it to start and keep it running. It takes about 50 cranks to get it to start. What else should I check?

[burnin240sx]

Is the start signal getting power?

double checlk the Start signal is sending a signal to the ECU when the key is in the start position. Since it was an AT does it idle high? If so ground the ecu neutral pin.

[vg33t]

Start signal pin 43 shows 0V with the key on and like .16 durring start. I grounded the neutral switch signal. What should I be reading at the start signal?

[USMCgetsome]

suggestion. cut and put it to ign switch 12vdc signal. Should help greatly.when ign switch is in on, you should see 12vdc to that pin.

[vg33t]

This chart says it should be 0 in start. so is it 12V in on and 0 in start?

[USMCgetsome]

correct because it is receiving 12vdc from the ignition relay. Ignition relay only provides power when in the ON position = key all the way forward. When in the off position it removes that 12vdc signal. therefore 0 = off 12 = on. there is no inbetween unless your battery is dead or has low voltage. keep in mind that you have a totally different setup than an r33 skyline.

[vg33t]

Ok I tried wiring the start signal to the ignition relay and it still does the same thing. The wierd thing is when you crank it, it fires right up then dies instantly. Its like all six cylinders fire once then nothing. Then after several tries it will sputter a few times then it will stay running. Once I get it started it runs great.

[USMCgetsome]

man that sounds like a few things here. I've know that to happen when people do not ensure proper connection on CAS, WATER TEMP SENSOR, MAF. one of them has to be unplugged or bad. also, check spark plug gap.

usually a maf would cause that prob.