Engine trouble.

[farrowby]

Hi all, finally got my car back and been running following starting problems after fitting new piper 285 cam and rpi stage 3 heads. Mechanic I used was poor to say the least, number of things wrong with the install but majorly had connected the water feed in the plenum to the air intake!! everytime the key was turned it was filling the engine up with water... luckly it didt apper to have done major damage. Have since put on about 750 miles and its now developed a couple of faults.

1. idle speed is around 2000 rpm it does eventually settle down but takes a while

2. Under heavey acceleration i am getting a miss fire/stall affect at hige end revs about 5000rpm. Not happening with medium/slow acceleration that I can tell.

Plan to clean stepper motor this w/end incase its that.

Anything else i should be looking at/for while i am under the bonnet?

tia

Tim

Forgot to say standard ecu, is the next planned upgrade when my pocket has recovered a little!!

Edited by farrowby on Friday 14th November 14:00

[rev-erend]

The oil breather feeds into the plenum - guess it's an easy mistake to put a water hose on to that .. similar size. Bit of a shame..

The heads and cam can now take a lot more fuel and air - so it will probably need a remap to make the most of what you have done.

I think as a temp measure you might be able to adjust the timing and fuel pressure to compensate but there is not really much you can really do without spending a few pounds.

Are you getting pinking at highter revs under acceleration ?

[farrowby]

not that i can notice, is almost like not enough fuel or fuel starvation, car jerks and not smooth acceleration is best i can discribe it. Plan to remap/ aftermarket ecu asap but funds dont allow. Had to change heads and cam due to wear etc, wouldnt have gone this way round if it were not thru need!

[blitzracing]

Use a test meter across the black and white wires coming from the lambda probes (extend the leads into the cock pit for a passanger to read) At tickover you should see it cycling between about .2 an .7 volts ideally at around 3/4 second interval. Then at 3400 rpm, or 3/4 throttle it should got to .7 volts or more and stay there. If its below this, its running out of fuel. This could be blocked filter, poor pump, kinked fuel lines or leaky fuel pressure regulator. More generally you may get away with just a variable fuel pressure regulator in preference to rechipping as the ECU is quite adaptive and you need at least 36 -38 psi fuel pressure at full load to keep it from running lean. Your problem sounds like it may be dropping well be below this. The lambda probes will tell you all you need to know, so only consider remapping if you cannot get the mixture right at full load, or if altering the fuel pressure for best full power readings makes the car snatch at lower revs, where the ECU has run out of compensation range. You also have to keep in mind, a bad misfire will also give low lamda readings, but the ECU can overfuel in this case as it tries to compensate so you might end up with sooty plugs. Well worth borrowing a fault code reader, as the ECU should pick up a fault this bad.

Mark

Edited by blitzracing on Friday 14th November 18:15