Miss fire at WOT - even when out of gear.

[kaeolian]

Ok gents I really need some help here to solve this.

I’ll try keep this succinct as it’s dragged on a bit.

The car started playing up and bogging down then refusing to rev, to solve this I put in new plugs, leads and coils. None of them solved the problem. I then found out how to read the engine codes and saw the car was in limp mode thanks to an error pointing to a failed solenoid.

So I replaced the whole solenoid box as well as the two joined to the front of the intake manifold, at the same time I replaced as many of the hoses that joined to it as possible as well. The solenoid box was new from japan and the two on the front of the manifold were second hand from Steve Watson on here. This solved the limp mode issue and the ecu is no longer throwing a code.

The problem I have now which I didn’t have before I touched the car, is that it’s now misfiring at wide open throttle. This happens either when driving or stationary out of gear.

I have no clue what to check now or even how to begin trouble shooting. Please help!

 

[Jit]

Can you get a video of it?

 

[kaeolian]

Will do!

 

[kaeolian]

Sorry still working on getting a video, its usually just me in the car so its hard. Another update to the problem after taking it to Boston Rotary Pete said its definitely over fueling. He checked over all the work I had done replacing parts etc and said it was all good and I hadn't messed anything up so that's good news.

After going on a drive with Pete its when the second turbo should be online that it miss fires like hell.

 

[Richard.C]

Sorry still working on getting a video, its usually just me in the car so its hard. Another update to the problem after taking it to Boston Rotary Pete said its definitely over fueling. He checked over all the work I had done replacing parts etc and said it was all good and I hadn't messed anything up so that's good news.

After going on a drive with Pete its when the second turbo should be online that it miss fires like hell.

Let me know if you need another pair of eyes on something, I'm in Lincoln.

It sounds like the issues came about after you did the other corrective work under the intake manifold, did Pete check that everything was plugged in where it should be and no open ports anywhere? Do you have a fuel pressure gauge installed?

 

[kaeolian]

Hey Richard that would be great, when are you free?

Yeah, Pete went through all the vac lines making sure everything was correct. I helped by holding up the technical diagram for him

Even though I put a whole new solenoid box in Pete advised just testing each of the solenoids individually just to make sure they are operating, so ill get some cables on them to see if I can hear them clicking.

I don't have a fuel pressure gauge installed, that was going to be my next troubleshooting step. A friend of mine said next item to replace is the fuel pressure regulator as we did the filter and it made no difference.

 

[jdmr_neil]

What ecu do you have?

Get a torch down around plugs and really check the wiring harness right down to the firewall for any damage. Also the two connectors down there.

If you have a commander is your water temp reading ok?

Any strong smell of fuel around below the uim, more than the usual rotary waft?

 

[JagKing]

Have you checked for boost leaks?

 

[kaeolian]

Standard ecu no mods. No damage to any of the wiring that I could see but I’ll double check.

No smell of fuel above the usual rotary smell.

Yes I’ve checked for leaks as best I can I’ve done a smoke test from the manifold. I’m not sure how else I can do a decent check.

 

[Richard.C]

Hey Richard that would be great, when are you free?

Saturday would probably be best bet.

 

[Jit]

Check your fuel pump and fuel tank. Take the pump out of the tank and see what it looks like (the pump and sock)

 

[Caine_1989]

Could it not be a fault with one of the secondary injectors if it's over fuelling at higher rpm maybe leaking or a bad spray pattern I'm not an expert with rotaries just no else had mentioned it yet

 

[kaeolian]

It could be I guess. If it was pump would the fuel pressure regulator not prevent it from over fueling?

 

[Jit]

Is it definitely overfuelling at the top end? I reckon first thing I’d do is get a fuel pressure gauge on it and see what’s what

 

[jdmr_neil]

I would also rule out the ecu by swapping to another oem ecu just to test.

 

[cib24]

How much do you want to bet it is the engine harness to coil wiring harness junction? This part was bad on mine when I bought the car and needed replacing before it could be mapped as it was bad and causing random misfires.

https://www.atkinsrotary.com/store/...Coil-Wiring-Harness-Junction-N3A3-18-05Z.html

 

[kaeolian]

Is it definitely overfuelling at the top end? I reckon first thing I’d do is get a fuel pressure gauge on it and see what’s what

That's what Pete at Boston Rotary told me, it's running a bit rich lower down as well as it pops whenever you blip the throttle and if you put your foot down and let off it makes a massive bang, everything apart from the back box is standard so I guess it shouldn't be doing that!

I would also rule out the ecu by swapping to another oem ecu just to test.

Hmm may be hard to find a 16bit ecu but if I could id definitely give it a try.

How much do you want to bet it is the engine harness to coil wiring harness junction? This part was bad on mine when I bought the car and needed replacing before it could be mapped as it was bad and causing random misfires.

https://www.atkinsrotary.com/store/...Coil-Wiring-Harness-Junction-N3A3-18-05Z.html

You think this could be causing it? It may well be, im just so confused by the many things which could be a factor on this one that I dont know where to start or what to replace first.

 

[Jit]

You need to find some time to take it to someone who has a fully working car and swap out those bits to check. Rather than than fork out on expensive parts. I’ll be surprised if it’s that loom. They’re not known to be a common failure point.

 

[cib24]

That's what Pete at Boston Rotary told me, it's running a bit rich lower down as well as it pops whenever you blip the throttle and if you put your foot down and let off it makes a massive bang, everything apart from the back box is standard so I guess it shouldn't be doing that!



Hmm may be hard to find a 16bit ecu but if I could id definitely give it a try.



You think this could be causing it? It may well be, im just so confused by the many things which could be a factor on this one that I dont know where to start or what to replace first.

I bet it is the wiring harness piece only because my issues were so similar. Swap one out from another car to see if it changes the behaviour of the backfire.

 

[Jit]

I have got a good 96-02 Harness piece of you want to rule it out as long as you pay postage both ways, I don’t mind you trying it out