280ZX - Advice for Starting Problem

SteveG

SteveG

Club Member
Hi,
I would like to ask if anyone in the group can give some advice on fault finding, for a starting problem with my 280ZX.

Over the winter I usually start the car up and back it out of the garage every couple of weeks. About a month ago I switched the engine on (fine), off and back on again and it was really "lumpy". You could feel the car slightly rocking. Since then I have started the car up a couple of times to investigate, then it went really lumpy, erratic, stalled and now it turns over but does not start.

There is a spark, proven with the timing strobe light on each plug lead in turn.
The plugs are smelling of fuel, and the tank has fuel.
The water temp sensor measures 3kohms when cold so I assume ok.
No obvious leaks or loose connections.

Any ideas, things to try next, welcome.
I do have the fuel injection manual pdf for the 280.

Thanks
Steve
 
johnymd

johnymd

Club Member
Put a new set of plugs in it then try.

If you are starting it up but not going for a drive to get the car up to temperature and using the full rev range, then the plugs will foul up. Do they look black and sooty?

In my opinion, its not good to start an engine without driving the car. Most of the engine wear is from cold starting as the oil is too cold to lubricate fully. It only lubricates properly when it hot and I'm talking about the oil being hot, not just the water.
 
Robotsan

Robotsan

Club Member
Sounds like my 280 when it was running too rich and the plugs were really sooty. Turned out to be one of the temp senders on the stat housing. That and maybe some of the various electrical connector plugs were dirty and slightly corroded - I took them all out and gave them a light sanding and that with one of the new senders seemed to fix it. It still is a bit lumpy if not started for a while, but after a few min its fine.

Maybe try adjusting the idle speed to keep it from stalling too? I would clean the spark plugs, then check the senders and check all the electrical connections you can find, and clean them all. Then try starting it again.
 
SteveG

SteveG

Club Member
johnymd said:
Put a new set of plugs in it then try.

If you are starting it up but not going for a drive to get the car up to temperature and using the full rev range, then the plugs will foul up. Do they look black and sooty?

In my opinion, its not good to start an engine without driving the car. Most of the engine wear is from cold starting as the oil is too cold to lubricate fully. It only lubricates properly when it hot and I'm talking about the oil being hot, not just the water.
Click to expand...
The plugs did look a bit black. I've been cleaning them up as they are not so old. I see what you mean about the cold starting, thanks
 
SteveG

SteveG

Club Member
Robotsan said:
Sounds like my 280 when it was running too rich and the plugs were really sooty. Turned out to be one of the temp senders on the stat housing. That and maybe some of the various electrical connector plugs were dirty and slightly corroded - I took them all out and gave them a light sanding and that with one of the new senders seemed to fix it. It still is a bit lumpy if not started for a while, but after a few min its fine.

Maybe try adjusting the idle speed to keep it from stalling too? I would clean the spark plugs, then check the senders and check all the electrical connections you can find, and clean them all. Then try starting it again.
Click to expand...
I have a new water temp sensor that I could try. thanks
 
Huw

Huw

Club Member
Sounds a bit like fuel starvation. Is the pump making a noise when you turn the key prior to starting it? If you turn the key to the position prior to firing it up, the pump should run for a bit to pressurise the system prior to starting. To check it properly, disconnect the starter (yellow wire to the starter) -and listen for the pump running. If not check the oil pressure sender connections (yes really) it’s in the starting circuit. If they are good, it might be the pump has sucked a load of crud up from being stood over winter. The pumps do fail if they ingest crap. Jack up the car and disconnect the pump and put 12v across the terminals to see if it spins. Worth also checking the pump relays are getting power before going that far I guess.

If the pump is making a noise ( ie working) then move on to check the EFI relay is getting power.

If all that’s working then you can get stuck into the cold start gubbins. Its unlikely the cold start components would stop the car starting, make it difficult to start but not stop it firing up.
 
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SteveG

SteveG

Club Member
Huw said:
Sounds a bit like fuel starvation. Is the pump making a noise when you turn the key prior to starting it? If you turn the key to the position prior to firing it up, the pump should run for a bit to pressurise the system prior to starting. To check it properly, disconnect the starter (yellow wire to the starter) -and listen for the pump running. If not check the oil pressure sender connections (yes really) it’s in the starting circuit. If they are good, it might be the pump has sucked a load of crud up from being stood over winter. The pumps do fail if they ingest crap. Jack up the car and disconnect the pump and put 12v across the terminals to see if it spins. Worth also checking the pump relays are getting power before going that far I guess.

If the pump is making a noise ( ie working) then move on to check the EFI relay is getting power.

If all that’s working then you can get stuck into the cold start gubbins. Its unlikely the cold start components would stop the car starting, make it difficult to start but not stop it firing up.
Click to expand...
Thanks. Given me some things to look at. The pump does run for a second or two before the "OK" on the dash.
 
Huw

Huw

Club Member
SteveG said:
View attachment 62601

Went out to the garage this morning with a fresh mindset. Started with wiring checks and straight away found this loose earth. I'll look it up later, but anyone which earth this is?

We are back purring again!

Thanks
Click to expand...
Excellent news. Thats the main earth for the injector loom.
 
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