rob TII

Hi guys having my first issues with non starting....Grrrr No its not fuel before anyone decides to jump in with the its flooded route.

Was driving along yesterday when it hesitated and the speedo dropped off like a total power loss but then it kicked back in literally after a second??

Every now and then I seem to have what feels like a misfire but then loss of power then its ok again.

Anyway after my drive pulled up sorted some stuff out and tried to start her up and it just sat there cranking over and wouldn't fire up. Scratched my head check the fuel pump was running which it was. Tried checking plugs but didn't have a spark plug socket to pull them out. Checked earth straps and fuses.

After another hour it fired up thought spot on got half a mile down the road and she cut out again and wouldn't fire back up. 4 hours stranded last night and gave up towed her back to my mates and left her on the driveway and got a lift home.

Any ideas?? Cant be fuel and cant be apex seals as when its running it runs fine apart from slight lack of power every now and then which i think could be related to the fault. I'm thinkin it could be a relay packed up or a coil gone down.

Thanks in advance guys

satch

iTrader: (1)

Next time your car dies or doesn't want to start you need to check for voltage on the Black wire that connects to the ignition switch. This wire provides constant voltage to the switch so it could pass voltage onto the relevant wires when the ignition key is turned. If the connection(s) along the way are faulty then a failure to deliver power to the switch will occur and the engine will either die or cut in and out. If the car doesn't want to start and the wipers and turn signals don't work w/key to on then this is evidence that the Black wire is not providing power to the ignition switch. The main ground to the engine could also be a likely culprit that would explain your troubles.

rob TII

Well had to leave her on my mates drive as she wouldn't start last night after 4 hours of tryin. where abouts does this black wire come from? Am i going to need to run a fresh feed to the ignition switch if this is the case?

Where abouts is the main ground to the engine as there are loads of earth wires that i checked last night and they all looked fine?

satch

iTrader: (1)

Black wire goes from the battery to the engine fuse box then the Black leaves the engine fuse box from the 100 amp main fuse then the wire goes to an intermediate connector or two and then to the ignition switch. Once you identify the Black wire as it leads to the ignition switch you can just ***** the wire with a pin to take voltage from rather then disconnecting the relevant plug.

The main ground on an S5 I believe is located on the UIM near the front passenger corner of the manifold but I could be wrong as I'm more familiar with S4's.


EDIT: Post #2 shows the location.
https://www.rx7club.com/showthread.p...ghlight=ground

Bamato

iTrader: (6)

Maybe since you state it's not flooding, is it getting fuel? When's the last time you changed your fuel filter? Got a way to check fuel pressure?

A dirty filter or sock(sending unit) can cause intermittent fuel delivery issues.

rob TII

Its getting fuel there is no issues there. I'm getting no spark and the speedo died off when it cut out but then came back on which suggests the electrical fault.

If i run a couple of extra earths from the engine to the chassis that should eliminate any engine electrical ground issues out?

If i'm not getting any voltage on the black wire to the igintion are we assuming a break in the wire or fuse issue?

If I am getting voltage on the black wire to the ignition feed whats the next possible solution?

satch

iTrader: (1)

The ground pictured runs to the ECU, adding extra grounds won't make the ECU ground any more effective. You basically have two choices, either redo the existing ground or add more grounds to the harness which plugs into the ECU with the first choice being the better of the two.

The Black wire travels from the battery to the engine fuse box and makes a connection at that point. The voltage passes through the Main fuse. A wire comes from this fuse which is Black/White. The B/W wire then connects to a Black wire. The Black wire then runs to the ignition switch. Any of these connections could possibly be faulty and contribute to your problem. The fuse connection could be corroded but generally the fuse itself is either good or it isn't.


Other problems could be a shorted wire and or poor connections in the associated wiring harnesses.

rob TII

I recently did a battery relocation to mount the battery in the boot so that I could route my NPR Intercooler but I'll have to check the wires that were associated with that mod. Strange that its taken a long time for the fault to happen.

I did the battery relocation nearly a month or more ago.

satch

iTrader: (1)

If the electric mirrors work as does the radio when the key is in the accessory position then you know the ignition switch is receiving power. Same goes for the wipers and turn signals with the key to "on." If these work and the car doesn't start then the Black wire is not the issue.

rob TII

Back to the drawing board then cos there all fine. Cd player works fine, wipers fine, turn signals fine and live feed to the black wire on the ignition switch is fine.

tried to find the ground that is in the engine bay and they all seem ok but couldn't trace back and do a continuity check.

So as it stands i have a full set of lights and switches the starter cranks over but not firing up and I have fuel but its not flooded.

So I either have a coil issue or an injector issue as there is fuel to the injector. Its like there is an immobiliser on the car but there isn't an immobiliser fitted.

satch

iTrader: (1)

The FSM has a list of the pin outs regarding the ECU so you could identify which are the grounds and go about doing the continuity test. Most of them are Black. I believe if you checked for voltage on the engine ground w/key to on there should be no voltage if the contact is good.

You also want to check the CAS. Disconnect the plug and clean it up and test the ohms level. Between the White and Red wires it should read 110 to 210 ohms and the reading should be the same between the Green and the Blue wires. Remember to not use the key in the ignition.

Focus on the leading coil as it is not necessary to start or run the car using the trailing coil. There is a two wire plug connected to the leading coil and the Black/Yellow wire should have battery voltage w/key to on. The other wire in the same plug is Green/Yellow. This wire should have about 5 volts w/key to on and as you manually turn the engine via the main pulley the voltage should briefly drop to 0 volts and then back to 5 volts. Also, make sure the coil(s) are bolted to the fender properly. To check for spark remove a plug wire from the coil bore and place the plug wire within a fraction of an inch (1/8th) of the bore and attempt to start the car and look for the spark.

Also, how do you know that you have fuel pumping into the engine? The front primary injector is Light Green, pin3W, at the ECU and the front secondary injector is Light Green/White, pin 3X. With an LED light in hand take the light to the battery and figure which wire to the light is the positive and which is ground. Take the ground wire of the LED and backstab it into pin 3W (front primary) and the positive wire to a pin that has voltage w/key to on which would be pin 1B ( Black/White) and attempt to start the car and if the injectors are being sent a pulsing signal from the ECU the light will flash repeatedly. You could do the same as well for the front secondary if need be.

rob TII

on the leading coil this is the coil which is a single coil to run both leading plugs? near the battery in the nearside front wing just behind the headlamp? If so I checked with a power probe and only getting a live feed to one wire w/key in the on position and with the key in the off position both wires were negative?

Thanks for all the help so far BTW i can do almost anything mechanical but electrics aren't my cuppa tea.

satch

iTrader: (1)

Yes. Which wire had voltage w/key to on? B/Y or G/Y?

To make sure the Main relay is working properly the B/Y wire mentioned above would have voltage w/key to on as well as the Black/White wire found at any of the emission solenoids.

rob TII

Well had a bit of fun and got her back home she struck up and run spot on as soon as i got to her after a few days. Had chance this week to check through some of the wiring and all seems to check out apart from and earth strap that went from the back of the engine somewhere to a spay terminal on the bulkhead which i cleaned up and has made a difference to the running and now seems a lot smoother.

Not fully convinced this has cured the cutting out and none start issue!!