Exhaust explosions 3.0 24v
During change from first to second gear (after full throttle) car makes small explosion in exhaust system and when engine is properly heated, starts to shut down. Obviously there is plenty of fuel in system. That can be seen also during acceleration, exhaust gases are black.
Did someone experienced this kind of problem?
Lambda probe is new, AFM works like clock and it is on factory settings. Sparkplugs are new (ngk platinium bpr6f), cops are working good and there are no leaks on injectors. Engine temperature sensor is in factory readings. Car runs on modified old type plenum ported to 43mm, along with intake runners. Exhaust system is also custom made and runs on two free flow silencers.
I'm running out of ideas.. Where else to look for eventual solution of problem? Can this be related to old type of plenum?
Did someone experienced this kind of problem?
Lambda probe is new, AFM works like clock and it is on factory settings. Sparkplugs are new (ngk platinium bpr6f), cops are working good and there are no leaks on injectors. Engine temperature sensor is in factory readings. Car runs on modified old type plenum ported to 43mm, along with intake runners. Exhaust system is also custom made and runs on two free flow silencers.
I'm running out of ideas.. Where else to look for eventual solution of problem? Can this be related to old type of plenum?
Re: Exhaust explosions 3.0 24v
Nothing wrong with plenum. Sounds like cam overlap. I get it on start up on my one car that has huge overlap. Its not typical of a gotech system as its on my haltec system. Injectors dont need to leak but maybe chech them on injectors machine as maybe one of them is overfueling chronically. I was playing o n ijector machine other day testing all my injectors and its not just a simple leak test. There are four tests you carry out. one of them being leak. With this machine you can set the rpm you want to test at etc. I ended up throwing away three injectors, the others were cleaned on the machine using a frequency agitator.
Put on tdc and check timing marks on back cams. Process elimination.
Put on tdc and check timing marks on back cams. Process elimination.
Re: Exhaust explosions 3.0 24v
Timing is ok, checked it twice; once during cam belt change and once after 3000 kms. Strange thing is that this explosion/choking thing happens only when engine is almost fully warm, but all components that could affect that seems to be on factory measures...
I'll test flow injectors - they were only cleaned but not tested.
Thank you for suggestion!
I'll test flow injectors - they were only cleaned but not tested.
Thank you for suggestion!
Re: Exhaust explosions 3.0 24v
ECU disregards Lambda at WOT, check fuel pressure.
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
Re: Exhaust explosions 3.0 24v
a friend of mine experienced a similar behaviour: he had fuel pressure falling on WOT after 4000rpm (Fuel pump tired)...
Re: Exhaust explosions 3.0 24v
Mike, you've found it! Did all measuring and totally forgot about fuel pressure - there was the problem. FPR died and I measured 3.1 - 3.2 bar on rail! In a day or two I'll test the car, but even at the first look at slider on maf there's a change in behavior. Now it hits max value on full throttle, which wasn't the case before.
Re: Exhaust explosions 3.0 24v
With the fuel pressure falling off is that a problem with the pump, the return regulator or something else??
MR1 Zig (I made rate!)
Machinery Repairman USNR
Machinery Repairman USNR
Re: Exhaust explosions 3.0 24v
Fuel pressure is directly proportional to manifold pressure.
As manifold pressure drops so does the fuel rail pressure.
This is to maintain constant flow rates through the injectors as flow is equal to the square root of delta pressure.
With manifold at atmosphere normal fuel pressure should, for most cars, be around 3 bar (45psi) and could (if you're going foot off at 100mph down a steep hill in first gear) drop as low as 2bar (30psi).
As manifold pressure drops so does the fuel rail pressure.
This is to maintain constant flow rates through the injectors as flow is equal to the square root of delta pressure.
With manifold at atmosphere normal fuel pressure should, for most cars, be around 3 bar (45psi) and could (if you're going foot off at 100mph down a steep hill in first gear) drop as low as 2bar (30psi).
Brett
Re: Exhaust explosions 3.0 24v
Yeah thats the normal progression of things, bcal....I wanted to know about the reason for the problem that killaz was having.
MR1 Zig (I made rate!)
Machinery Repairman USNR
Machinery Repairman USNR
Re: Exhaust explosions 3.0 24v
It's normal thing for fpr to fail, it stands "closed" and gives max pressure (and maybe bit higher) for wich is calibrated - to clear things, measuring was done at idle, where pressure should be from 2.6-2.8 bar, I had 3.2 bar.
Fuel pump makes about ~4.5 bar in system, so it doesn't suffer this malfunction.
Fuel pump makes about ~4.5 bar in system, so it doesn't suffer this malfunction.