VietShiet

I just had a rebuild done... and also a tune. The car cranks up horribly just like it was still blown.. It cranks and manages 300rpm... then slowly rises to 1100rpm. Some times it cranks to 300rpm then bounces over 300 up to 400 then drop back. When ever i crank the car i also have to put a lil gas. The car cranked fine before it blew, always cranked up to 1200rpm then drop to 1100rpm never failed to start.

The 2nd problem would be that the car's idle would drop to 300rpm when i would shift to neutral then press on the brakes to approach a red light. The idle would return to 800rpm right away though but still.. i never had these annoying problems with my fc before. My fc is a s4 with a complete 13-rew transplant running a Haltec ecu.

The only difference between when my engine was blown till now is that the car does not wobble when the idle drops. Other than that it still has those problems of a blown engine... Can anyone help me out? I can post some videos shortly on youtube if you wish.

rx927

iTrader: (3)

Did you drive the car for some time after the rebuild or this was first attempt?

Was this a stock rebuild or did you go with upgrades, block off plates,etc?

That idle drop when in neutral might be dashpot adjustments or trans settings if you have a pfc.

I guess start with searching for issues with:
Map sensor
Grounds
Throttle Position Sensor
Simple things like fuel pump/pressure, plugs,wires, coils.
Major vacuum leaks

VietShiet

The car ran in for about 1500km already, stock rebuild using 1 piece unbreacker SCR seals.

WaachBack

iTrader: (21)

Do a compression test.

arghx

iTrader: (3)

somebody pulled out the fast idle system and/or the ISC valve.

VietShiet

ok guys, i started the car up today and it cranked to 1100rpm right away which was PERFECT, i then took the car for a 20 minute drive and then shut her down, when i cranked her up again it only cranked to 300rpm and bouncing off 300-300 rpm then slowly rising, is this a weak starter motor?

rx927

iTrader: (3)

Why arent you diagnosing with everyone's given advice?

If your car actually turns on but with effort (open throttle/building up by itself). Starter would not give those symptoms.

sbnrx7

iTrader: (4)

Check the fuel pressure regulator.

alexdimen

iTrader: (13)

Your starter never spun your engine at 1100 rpm. That'd be one bad *** starter...

You're confusing cranking speed with the engine speed after start-up. You have an idle problem. These guys have pointed you in the right direction: compression and idle control system. rx927 even listed search terms.

VietShiet

ok man, well the builder did a compression test and they were in the mid 90s like wtf? he said the battery was kinda low so the start motor only spun at 200rpm or some **** and the true reading would've been something like 104-106 both rear and front. Is this guy dodging me out? He also said the Haltec E6A or something doesn't have a cold start but i searched on the Haltec site and the manual said there is a cold start. I paid 650 for the dyno/tune plus having my exhaust re-webbed.

arghx

iTrader: (3)

There are all sorts of things in the Haltech that can contribute to bad cold starts. It may not have enough warmup fuel enrichment for example. Why don't you post in the Haltech section?

And a weak battery can definitely turn the starter slower, which will make it harder to start the car.

thewird

iTrader: (8)

One piece seals have funny cold starts. I speak from experience. Now of course there can still be something wrong with your cars idle setup or tuning parameters but just letting you know

thewird