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View Full Version : surging issue when hot



rob101
05-15-2007, 09:17 PM
my e28 528i (l-jetronic m30) has this PITA issue that occurs (feels like hot fuel surge) after long drives it just surges like mad when you go up hills slower at higher rpm and up even slight hills on the freeway (at higher speed). at first i thought it was igntion so i replaced cap, coil, rotor and a broken lead also got the AFM "reconditioned" which I found was basically paying some talentless dickhead $350 for nothing(next time its going to the US).
I thought it was a fuel problem got my mechanic down the road to check the fuel pressures he says they are okay. he is replacing my fuel filter. he will be getting the injectors cleaned and flow tested.

any ideas if this doesn't solve the problem?

I'm getting fed up with this honestly I can't work out wtf is wrong with this thing.

BigKriss
05-15-2007, 09:21 PM
looks like your adressing all fuel and ignition issues. no other ideas dude.

rob101
05-15-2007, 09:25 PM
well i read somewhere it could be the ECU on the way out. it started off only happening once every couple of trips now its more frequent. i had to take 2 attempts getting up a hill from the parking lot behind a shop last time i drove it. It'd be good to throw it to some of the mechanic gurus here. cos I am bad at diagnosis and i really feel like a git for throwing parts at it. but honestly i can't work it out.

GJPinAU
05-15-2007, 11:36 PM
I'm putting my money on the fuel filter

Ross
05-16-2007, 07:42 AM
Sounds like it's starving for fuel. If the filter doesn't cure it try disconnecting and plugging the vac line to pressure regulator and see what happens.
EDIT A lean surge actually is what this sounds like. So either too little fuel or too much air, check also for vac leaks.

rob101
05-16-2007, 04:12 PM
Sounds like it's starving for fuel. If the filter doesn't cure it try disconnecting and plugging the vac line to pressure regulator and see what happens.
EDIT A lean surge actually is what this sounds like. So either too little fuel or too much air, check also for vac leaks.
yeah. there are heaps of vac lines everywhere in L-jet mechanic found a few disconnected and one that we couldn't work out were the hell it goes. Fuel pressure was normal though just under 260 kPa (its meant to be 2.5 bar-3.0 bar or roughly 250-300 kPa).
I miss my cars my e34 is in the shop getting the result of some negligent driver running into me repaired and this one I am worried that with this problem it'll strand me somewhere. I've been driving my parents echo, what a POS. I feel like i am going to die it when i drive it on the freeway it has shocking vision, shocking brakes, poor seating position (was designed for some kind of praying mantis), bad gearbox, rattles and buzzed and doesn't really feel like its connected to the road :p .

GJPinAU
05-16-2007, 06:07 PM
yeah. there are heaps of vac lines everywhere in L-jet mechanic found a few disconnected and one that we couldn't work out were the hell it goes. Fuel pressure was normal though just under 260 kPa (its meant to be 2.5 bar-3.0 bar or roughly 250-300 kPa).
I miss my cars my e34 is in the shop getting the result of some negligent driver running into me repaired and this one I am worried that with this problem it'll strand me somewhere. I've been driving my parents echo, what a POS. I feel like i am going to die it when i drive it on the freeway it has shocking vision, shocking brakes, poor seating position (was designed for some kind of praying mantis), bad gearbox, rattles and buzzed and doesn't really feel like its connected to the road :p .
Still better than walking ;)