03/1997 Probe 2.5 V6 - Crank No Start/Spark

Post by **rockits** » Tue Jul 22, 2025 11:06 am

jrh wrote: ↑
Tue Jul 22, 2025 10:55 am
I may be wrong here but I think you need a working key fob , even with a by-passed
immobiliser.
And NEVER , NEVER leave a spark plug lead disconnected.

I was thinking if this was the case as well and if I needed a working key fob. I wondered if this would still be the case if the Bosch unit was removed entirely though but don't know enough about the car and all systems just yet.

I have found and ordered another Bosch unit that comes with the keyfob just to test, play and understand some things. Fairly cheap to test/play/learn.

I might send my disty off to be tested and repaired as that is also an options so semes to make sense to try in the first instance.

I did take a lead and spark plug out to test for a spark but left the spark plug in the lead to hold to ground to test for the spark. Not that I would ever leave a spark plug lead unplugged but what would happen if you left one unplugged (I am guessing with no spark plug in you mean?) then tried to start?

Post by **jrh** » Tue Jul 22, 2025 1:29 pm

A working system creates a very high voltage , which discharges itself to 'earth' at the
point of least resistance. The gap on your spark plug.
If a lead is left disconnected , that voltage has to deplete somewhere else , if that route takes it back into the low voltage transistors....................goodbye HT system.

Post by **Micron** » Tue Jul 22, 2025 3:21 pm

jrh wrote: ↑
Tue Jul 22, 2025 10:55 am
I may be wrong here but I think you need a working key fob , even with a by-passed
immobiliser.
And NEVER , NEVER leave a spark plug lead disconnected.

You no longer need a fob once the Bosch moby has been bypassed John.

Post by **rockits** » Fri Jul 25, 2025 12:32 pm

I've received delivery of the new disty unit now so nice job for the weekend.

Does anyone know if there is anything specific or weird and wonderful that needs to be done replacing one of these please?

I'm guessing disconnect the battery and leads, unbolt the previous one and remove, then replace?

Will look to mark and try to keep exactly the same fitting position as there are elongated holes on the mounting bracket to allow the unit to be rotated a little. Guessing for timing tweaks.

Post by **Kit** » Fri Jul 25, 2025 3:01 pm

It's got a off set key way, It's can only one way

Kit

Post by **rockits** » Sat Jul 26, 2025 11:17 pm

Managed to get it started this afternoon. It wasn't the disty. Just me being part dim!

When I bought the car the fuel rails with injectors, the complete airbox, MAF a few hoses and lots of nuts/bolts were off the car. Managedto work out where everything went to get them all back together.

After it didn't start or spark I checked all the fuses and relays. On opening the main fuse box under the bonnet I noticed the F/P 30a fuse had been removed and left out to the side. I'm guessing the previous owner didn't want fuel coming through while he was checking for spark or something. So I left it out as didn't want fuel just yet either. However, it seems this is a dual fuel/power fuse and I thought it was just fuel! Doh!!

So plugged that fuse back in and it started right away! Just running a little rough and idling erratically. I've also got a slight fuel weep from the end of the front fuel rail so suspect the existing copper washer might need replacing on the end as the bolt goes in. Should be able to find and replace that easy enough. So don't want to run it too much just yet until I get a nice dry fuel rail!

The weird thing as I was putting it all back together again this afternoon is for the life of me I can't see or don't seem to have a cable/connector that plugs into the right hand side of the airbox to the MAF. Looks like there is a connector on the airbox/MAF but I don't have anything to plug into it. I took all the airbox out again and look everywhere to see if it had fallen down or was hiding somewhere but buggered if I can see or find anything.

I've added a pic of the MAF and the connector and just trying to find some pics on the web to see. That must tell the ECU about the air flow so could explain it running erratically without this. Although I thought on many cars I have worked on if you unplug the connector to the MAF it just uses a default/base map or something so is not optimal but would still run OK.

I am guessing it should have a cable/connector to plug into that?

Post by **cpt black** » Sun Jul 27, 2025 9:01 am

Deffo need the Maf connecting that will effect the idle as not metering the air flow
you may have trapped the connector under the airbox when you installed it

Post by **Kit** » Sun Jul 27, 2025 10:30 am

Well, look on the positive side, you now have a spare Dizzy and, you have learnt a lot about these carz

Kit

Post by **rockits** » Sun Jul 27, 2025 1:19 pm

cpt black wrote: ↑
Sun Jul 27, 2025 9:01 am
Deffo need the Maf connecting that will effect the idle as not metering the air flow
you may have trapped the connector under the airbox when you installed it

Thanks for that. I thought that should be the case but always best to get a second and better qualified opinion. I look for ages but couldn't find anything but going to take a look again after getting it out of the garage in the daylight. Must be somewhere surely. Might take the battery out in case it is hiding under there as think the previous owner put a new battery on it.

Post by **rockits** » Sun Jul 27, 2025 1:23 pm

Kit wrote: ↑
Sun Jul 27, 2025 10:30 am
Well, look on the positive side, you now have a spare Dizzy and, you have learnt a lot about these carz

Kit

Yes, this is very true. I tend to learn pretty fast and hopefully the Probe is a little less complex than some more modern cars. Still got a lot more to learn though!

At least if I'm happy the engine and car is very good. Which I think it is. Then I can start working my way through the list of need to do's. Going to do water pump, timing belt, pulleys, alloy refurb, new tyres, new brakes all round, fuel/oil/air filters, plugs and any other consumable that needs doing.

Need to sort the fuel weep out top of the priority list though. At least I can move it then rather than having to bump or push it around.

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03/1997 Probe 2.5 V6 - Crank No Start/Spark

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