What The Hell's Wrong With My Car?

[Fury1630]

Today I fitted a vacuum gauge - just because I had one, it was jumping a bit, so I thought I'd check the throttle body balance, I was connecting up the pipes to the balancer, fiddling under the inlet manifold where the coil pack is when the engine suddenly started running rough, it could just barely idle.

I pulled the plug lead one at a time & they all seemed to have a spark, but none of them made the engine any worse when it was off. All four exhausts were hot.

I faffed with all the leads at the coil pack end in case I'd disturbed something & eventually convinced myself that 1 & 3 had a weaker spark & bought a new coil pack, fitted it & bingo! car back to normal

So I set about balancing up the TBs again & made the mistake of turning on the ignition when the fuel rail wasn't bolted down (the bolts have to come out to remove the airbox) then I messed up an injector o-ring & had to go to Screwfix for a nitrile o-ring assortment, found one to fit, re-assembled & it's running like a dog again

I wanted to use it to go to Biggin Hill tomorrow too, looks like I'll be dieseling.

When it is apparently running on two cylinders it keeps "sneezing" on No.3 & sometimes No. 1 & I can see the flame behind the butterfly.

[b33fy]

What management is the engine running Tony? If Edis 8 is fitted worth, checking connections back to module including earths etc. It may also be something simple like arcing ht lead across that pack, caused by a break in the lead. might be worth checking leads and connections for integrity.

[Fury1630]

Omex 600 & the leads are all newish.

[Matth93]

Could it be that you’ve disturbed something and caused a air leak on the manifold

[Fury1630]

Could it be that you’ve disturbed something and caused a air leak on the manifold

Possibly, but investigations this evening suggest it's running really rich. To get it to idle I have to hold the throttle about a quarter open & it's smoking & sooting the plugs. I've checked the cam timing in case one of the wheels jumped a tooth, but that all looks OK. I also put the old coil & plug leads back on, but that made no difference.

Tomorrow I'll connect up the laptop & see what the TPS is doing & make sure it's getting a proper signal from the crank position sensor. I'm pretty sure it's something simple, but at the moment I can't work it out.

[b33fy]

I’ve left the vacuum pipe off the manifold to the MAF sensor a couple of times when doing the head gaskets, which causes similar running issues. Telling the ecu there’s more air than actually is and over fueling.

[Fury1630]

Mine hasn't got a MAF meter, so it can't be that

[b33fy]

Mine hasn't got a MAF meter, so it can't be that

Sorry Tony Manifold Absolute Pressure sensor (MAP)

[David T]

Broken the wires inside one of the connectors, eg ECU to coil pack?

[Fury1630]

Mine hasn't got a MAF meter, so it can't be that

Sorry Tony Manifold Absolute Pressure sensor (MAP)

Hasn't got one of those either The Omex relies on crank speed & throttle position to calculate load.

I'm going to check the throttle linkage first (as I made it ), then as David T says, look for wiring problems.