New Engine Won't Start

[rsx84]

Ok, i put in an rb25det into my r31 last week end, its an auto and has all been wired to suit, fuel is flowing to the engine but its not firing, we got spark to #1 plug then checked #2 and nothing, then we checked #1 again and nothing there???

also the plugs were dry which after 20 min of cranking the engine over trying to get it to start, i'd asume the plugs would be wet with petrol??

we tried to do timing last night but lost the light, tonight with lights we'll look at the timing and check injector flow and palse...

looking for ideas before i have to take it to a work shop....

[predator]

Check for 12v at the white wire going into the ignitor during IGN on. It should be fed through the IGN relay down near the ECU (one of the two main blue relays).

To check injectors are getting voltage, pull off an injector plug, and check for voltage during cranking.

Next thing is making fuel is actually getting to the injectors. Do you get the hum of the fuel pump when you flick on the IGN ?

[BHDave]

Just the usual obvious ones when wiring an rb25 engine into a non factory body.

Make sure the coils and injectors have power. The coils probably will if you have maintained the 2 relays near the ecu as all you need to do there is give it get constant power to one side of the relay and the rest of the loom doesn't need to be touched. Injectors will come straight off a switched ignition through the big SMJ plug so check that they are getting power.

The power for everything in the rb25 comes from the big SMJ and a surprising number of things are powered off different pins on this plug so just trace every wire that runs direct from the plug into the loom and figure it out from there. In most case the ecu uses negative triggers so almost every wire that runs straight to a sensor plug off the SMJ is a switched ignition. There are a few exceptions like the temp gauge and a couple ot others i cant think of right now though.

[Abo Bob]

Have you put spark plugs in? That's what I forgot.

Also it's an auto so inhibiter switch issues?

[Duncan]

Have you put spark plugs in? That's what I forgot.

hahah hhaha hahahhaha

ahhah

ahahhahah

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ahahahhaha

that still makes me laugh

[rsx84]

the loom for the engine and auto box are from an r33 and have been professionally wiried to mate with the r31 system, the only issue i had there was tyhe neutral saftey switch, which i have bridged for now for starting perposes...

i just spoke to the bloke who wired it and he suggested manually checking for the injectors firing, first testing power is getting to #1 injector (test light on each injector wire, testing one of the 2 wires at a time), if power then remove the CAS and turn it with the power on so i can hear if the injector are firing...

oh and it came with plugs already installed..... HEHE...

Edited June 13, 2006 by rsx84

[mad082]

is it a series 1 or 2 motor? series 1 have a square TPS sensor, and an ignitor box at the back of the rocker cover the series 2 has them in the coil packs (or ecu not sure). there may be a chance that some of the coils are mixed up (some series 1, some series 2), or the ecu is the wrong series.

[rsx84]

is it a series 1 or 2 motor? series 1 have a square TPS sensor, and an ignitor box at the back of the rocker cover the series 2 has them in the coil packs (or ecu not sure). there may be a chance that some of the coils are mixed up (some series 1, some series 2), or the ecu is the wrong series.

it must be a S1 as i have an ignitor and TPS, all the coil packs seem the same, identical to rb20det coil packs..

i'll check there is power to the injectors tonight then go from there, if there is spark but its not starting i'd say its injectors.. we can also test there flow tonight to just in case??

Edited June 13, 2006 by rsx84

[mad082]

sorry, should've explained better. both have a TPS. series 1 have a small rectangular one, the series 2 have a rounded plug, with another unused plug above it.

[rsx84]

sorry, should've explained better. both have a TPS. series 1 have a small rectangular one, the series 2 have a rounded plug, with another unused plug above it.

yeah S1 then....

[blind_elk]

The really (stupidly) obvious question - the fuel hoses are connected to the rail correctly?

[rsx84]

The really (stupidly) obvious question - the fuel hoses are connected to the rail correctly?

yeah they are in the correct order, checked and double checked, fuel filter line connected to the fuel rail, return line coming from the fuel regulator??

[rsx84]

To check injectors are getting voltage, pull off an injector plug, and check for voltage during cranking.

Next thing is making fuel is actually getting to the injectors. Do you get the hum of the fuel pump when you flick on the IGN ?

Sorry Gordon didn't read the last part of your reply, i have wired in a relay so the r31 pump is working fine, primes when the key is turned and can feel the pulse in the fuel line when its cranking, then no pulse just after we stop cranking.

if there is no power to the injector what would be the fix for this?

[James_03]

On the SMJ plug will be a light grey wire, this is the 12v for all the injectors.

The ecu then pulses an earth to each injector. Check that the light grey wire has a 12v constant on it.

You should be able to take out one of the injector plugs and with the grey wire hooked up to a 12v constant get that same reading with a multi meter off one of the injector plugs.

You will need to earth the multi meter against the car, then measure the reading from the grey wire in the injector plug.

Just to make sure you hooked it up right.

Also you should place a 30amp inline fuse between the grey wire and ingnition. As R33 has this too.

Edited June 13, 2006 by James_03

[predator]

yeah.. I was also going to suggest the 12v to the grey wire as well. It's a thin one, but it is vital to hook up or you won't get any power to the injectors.

That was one of the problems when I couldn't get mine first started. I reckon it's about a 90% chance yours is the same problem. If not I might be able to drop around one night this week and go through a few other checks, seeing as you're local.

[rsx84]

yeah.. I was also going to suggest the 12v to the grey wire as well. It's a thin one, but it is vital to hook up or you won't get any power to the injectors.

That was one of the problems when I couldn't get mine first started. I reckon it's about a 90% chance yours is the same problem. If not I might be able to drop around one night this week and go through a few other checks, seeing as you're local.

Thaks mate, i tested the #1 injector plug last night, using a test light i placed one end on the body and the other to each terminal one at a time and cranked it, the light never flashed, i also spoke to Kev, the bloke who wired the loom, he thinks i may have blown the relay but he's coming to the coast this sat and will stop in to have a look.

the power to the ecu has been taken from the original r31 ecu plug next to the AFM, kev said the power to the injectors comes from there to. i think i'll wait for him to came down and he can sus it all out...

gordon, i was specking to syphon about your conversion and he said you had a few problems too, he also said yours is running perfectly now..

Edited June 13, 2006 by rsx84