crappy running

[jon haines]

Help please i am at the point of despair, over the last 2 years i have had intermittent running probs, car wont tickover wont run on light throttle and keeps going out of tune, one day its fine next its crap. i have replaced airflow,cold start, temp sensors, throttle pontentiometer,coil,ignition module,plugs,leads im sure ive missed something and my mechanic is mystified says never encountered such probs on rover v8 before. every time we replace something it runs great for a few weeks then back to crap if it wasnt for the joy of when on song i would have got rid ages ago.

[CarbonWedge]

It could be the ECU, I had to replace mine and went through the same as you in changing all of the usual suspects yet the fault remained and was completely un predictable, could happen anytime any where, and made the car virtually undrivable. It took the garage a long time to figure it out.
Maybe someone has one on here they could loan for a while. Hope you get it sorted soon!

[TVRleigh_BBWR]

Mine is still out on loan, but welcome to borrow once it comes back.

[Ivan Bland]

Jon,

There is an ECU for sale on ebay at the moment. I bought one some while back and intend to try it on my 350I this weekend in an attemptto get rid of an occasional miss fire. I too have changed plugs, leads etc but it is still there and annoying.

[jon haines]

thanks for your help i think ecu is the way to go.

[Wedg1e]

jon haines said:

thanks for your help i think ecu is the way to go.

If you're handy with a soldering iron, just reflow all the joints on both boards, that usually fettles it. Failing that, a few people on here are competent if you're near anyone...?
Another ECU may not exhibit the same symptoms but it's also unlikely to be a good match for your airflow meter as they were calibrated as a pair.

Certainly the symptoms you describe could be ECU-related, I had no end of grief when mine played-up. 'Course it could be an air leak, or recurrent probs with, say, defective coolant temp sensors...

[honestjohntoo]

I was wondering what engine/system you had and checked the profile. Oh Dear, something really changed since penning the notes therein.

jon haines said:

i have had my 350i since 2004 now and it is the best in a list of rover v8 engined cars i have owned. totally reliable.have spent a bit bringing her up to scratch and improving on what shes got and loved every bit of it.

Assumimg its the same car, you have my sympathy, sometimes they simply defy the best efforts we can throw at them.

Must admit, it does smell of an ECU prob, but one also wonders, though, bearing in mind most components on the standard flapper (with the exception of Ign Amp, Throtpot and maybe ECU) are pretty much bulletproof and the majority (>80%) of system problems are caused variously by rogue air leaks and wiring/connector faults, whether any testing has been done to find if components were faulty before being replaced?

Of course, it very much depends upon ones familiarity with the system, workshop skills and/or the ability of assistants, but when these systems first hit the Rover dealerships in 1982, selected workshop staff went on technician training courses to learn how to diagnose. That knowledge is now largely unavailable, and for hobbyists, expensive frustration takes over.

All is not lost and I recommend you have a look at this 15 point health check which should identify the intermittent source of your problems, particularly items 12 and 13, but dont overlook the other parts.

When it come to further appreciation, pop into this archive for everything you need to know about the Flapper Efi.

If you search back through this forum there are some pretty neat processes spelled out in great detail for finding intermittent ignition probs too.

Edited by honestjohntoo on Friday 30th April 23:04

[jon haines]

Thanks everyone for your help/advice. i have had wiring checked and also checked for air leaks both being ok. i am fortunate in that the mechanic who looks after it is in his late 50s and old school with lots of experience of these engines and enjoys tinkering with me car and dosent fleece me for labour in fact i dont think he charges me for the all the time he spends on it, i might have a look at soldering and those sites mentioned are in my favourites on my computer.