Boost Hesitation??

LTurbo · Post by **LTurbo** » Tue Oct 06, 2009 1:11 pm

Having an issue with my EA82T.

When the turbo begins to spool up low in the rev range, the engine hesitates briefly before grabbing again and moving through the rest of the rev range normally. This only happens occasionally and with no pattern I can see.

I initially thought it would be a vacuum leak, but I gave the engine a quick look over and all the vacuum hoses seem to be fine. Next I am checking the AFM and then spark. Any other ideas to what may be causing this?

subybrumby · Post by **subybrumby** » Tue Oct 06, 2009 5:35 pm

I'm interested in this thread as my EA82T does the same. More like a flat spot at low revs, then it spools and off she goes.

phillatdarwin · Post by **phillatdarwin** » Tue Oct 06, 2009 6:40 pm

if u are looking for a vacuum leak just spray some carbe cleaner around all your vacuum pipes with the engine running and if it revs up u have a leak in that spot as if u can not hear them u will find them this way .
hint just spray at one spot at a time.

Post by **Captain Obvious** » Tue Oct 06, 2009 6:41 pm

check the leads and plugs, mine did this for a while and i replaced the leads and plugs and it cleared up

Gannon · Post by **Gannon** » Tue Oct 06, 2009 7:36 pm

Have you ever had your injectors cleaned.

I had a similar problem, and it stopped after i got my injectors serviced.

twilightprotege · Post by **twilightprotege** » Tue Oct 06, 2009 8:39 pm

going off my own experience with a (probably) similar problem, and with no mean to scare - have you checked for exhaust gas in your coolant? have you checked for coolant on number 1 spark plug/lead - particularly coolant leaking from around the thermostat, or from the bolt hole to the right of the thermostat and the front of the spark plug? both of those only happened to me while reving the engine

for me, i had the same problem as you. the engine was missing as soon as boost was coming on. a little while later it was missing a bit more often - namely under wot. later it became totally random even happening under normal throttle just driving along.

as soon as i put a bolt in that bolt hole and replaced and resealed the thermostat, the car has been fine. still uses a tiny bit of coolant, but otherwise ok

steptoe · Post by **steptoe** » Tue Oct 06, 2009 10:59 pm

if it is intermittent, I wonder if it is your fuel pump giving up the ghost. Yours, if original, would be same age as mine when it was shot, a few less kms on mine at 188,000, it would show its weakness at boost, then needed a hit with a hammer and powered direct to crank it up. Replaced it with a VL Commodore efi fuel pump.

Any ECU codes throwing on the LED below steer column?

Run low on fuel lately? Bought fuel from any suspect low volume quiet town sites? Fuel filter inspection at least, disconnect it an run fuel out of it backwards over white paper. No E10 mix ?

Tell me my earlier post got you inspecting your fusible links for integrity.I was getting some early signs of mine going before the coil frazzled and then the big electrical storm within. The black one is the one relating to ignition. Your problem is bound to be fuel or ignition eh ? Check your battery terminals for cleanliness and tight. Check coil connections and inside coil tower and dizzy cap plug terminals for corrosion crud, and earth screws at body to motor etcfor loose contacts

LTurbo · Post by **LTurbo** » Wed Oct 07, 2009 8:36 pm

subybrumby wrote:I'm interested in this thread as my EA82T does the same. More like a flat spot at low revs, then it spools and off she goes.

Are you experiencing this intermittently or is it a regular occurrence?

LTurbo · Post by **LTurbo** » Wed Oct 07, 2009 8:41 pm

steptoe wrote:if it is intermittent, I wonder if it is your fuel pump giving up the ghost. Yours, if original, would be same age as mine when it was shot, a few less kms on mine at 188,000, it would show its weakness at boost, then needed a hit with a hammer and powered direct to crank it up. Replaced it with a VL Commodore efi fuel pump.

Any ECU codes throwing on the LED below steer column?

Run low on fuel lately? Bought fuel from any suspect low volume quiet town sites? Fuel filter inspection at least, disconnect it an run fuel out of it backwards over white paper. No E10 mix ?

Tell me my earlier post got you inspecting your fusible links for integrity.I was getting some early signs of mine going before the coil frazzled and then the big electrical storm within. The black one is the one relating to ignition. Your problem is bound to be fuel or ignition eh ? Check your battery terminals for cleanliness and tight. Check coil connections and inside coil tower and dizzy cap plug terminals for corrosion crud, and earth screws at body to motor etcfor loose contacts

Nup did not see your post about Fusible links, can you gives us a link to it? Will do all your other suggestions. I am fairly sure its a fuel/spark problem, all sensor are okay although I have still to check the AFM.

Not a fuel problem either, I have been through a few tanks with this same issue occurring.

subybrumby · Post by **subybrumby** » Wed Oct 07, 2009 11:40 pm

Lturbo, When I bought the car, it went like a rocket and was really responsive. The engine is in an 89 Brumby mated up to a five speed box. I then got faultering in the engine and finally tracked that down to a loose fuel pump relay.

Now I don't know much about computers, but the engine is managed by a stinger from EMS, and whether it has done something to compensate after that or what, I don't know. But the engine has a definite flat spot as you hit the throttly from idle. Its there all the time. Once the revs pick up and the turbo spools, away you go. There is also a smell of fuel like its running rich and I would say its probably a bit heavy on fuel. I also see that the wirings a bit hotch potch and that the wire from the exhaust (oxygen sensor?) is not even connected. I was always going to send it for a tune at a performance garage in Brisbane where it had been done before according to receipts that were in the glovebox.

So, yeah, it drives ok and sits up on cruise on the highway, but coming off the clutch off idle, there is what I would call a definite flat spot. Its annoying and I'll get to it, probably by a tune as previously said. I did find one small vacuum hose off, but when I reconnected, it didn't seem to make much difference. I like the idea of spraying the carb cleaner around. Might try that. Incidently, it idles really well and feels well balanced.

phillatdarwin · Post by **phillatdarwin** » Thu Oct 08, 2009 12:05 am

sounds like your oxygen sensor is a big part the proloms as it dos not know how much fuel to put into the engine .

steptoe · Post by **steptoe** » Thu Oct 08, 2009 9:01 am

showthread.php?t=14769

try this link

I agree , subybrumby woul be better off investigating O2 hook up.

LTurbo · Post by **LTurbo** » Mon Dec 07, 2009 10:12 pm

Managed to solve this I think. Tracked it down to a dodgy solder in the o2 sensor wiring. Re-soldered it and the engine has been running without issue now for a couple of weeks.

Just not sure how this was causing the issue though

Suby Wan Kenobi · Post by **Suby Wan Kenobi** » Tue Dec 08, 2009 5:06 pm

Dads car was doing this it ended up being the plug for the AFM, it was corroded alot. Had similar on mine a few years ago and it was water in the knock sensor.

Gannon · Post by **Gannon** » Tue Dec 08, 2009 5:39 pm

Theoretically, the o2 sensor shouldn't make a difference, as the ECU ignores it once you are making boost or the throttle is more than 50% open.

Where did you repair the solder?

steptoe · Post by **steptoe** » Wed Dec 09, 2009 9:44 am

If in doubt read the destructions. Any after market O2 sensor I have seen comes with instructions in many languages and pics in order to help you get it working and connected correctly. In these instructions they say DO NOT SOLDER use only the special connectors also provided. Something to do with oxygen referencing in coper wires?

Thomas forgot to tell us he fixed it initially by adding boost

steptoe · Post by **steptoe** » Tue Aug 31, 2010 9:38 am

Now I have same sort of random dud spot

Rule out ECU as its only purpose is EGR control and that is it, rules out O2 sensor
Rule out leads cap and rotor new
The spark plugs were OK but forgot to swap over the new ones from old donk
FL's gave trouble this time last year in a BIG way

Have got boost gauge flutter at 5500 rpm or so but this was fixed with new valve springs - I thought, but it is back now - suspect it is wastegate diaphragm (that is a hard word to type!)