AE86 slow on the revs and hesitant.

[krullibull]

Hello!

Just got my AE86 back together and on the road, unfortunately the engine won't run properly . It's reeeally slow on the revs and throttle response (like a Volvo 740 GL) and lacks a fair bit of power. To describe the fault best as I can while driving, the car revs (rather slow) to about 3k then it's really slow and hesitant until after 5k where it gets a little bit better. It smokes quite a lot when stepping of the throttle on high revs, both white and some blue.

I've reset the ignition timing correctly 2 times as I first thought this was the problem. At 10 BTDC the car is barely driveable, you have to rev it hard and release the clutch slowly. Currently I'm running 15 BTDC and the car is driveable but slow revs and throttle response and hesitant on acceleration.

It drove wonderful last year before it went i the garage. Only things I've done to the engine over the winter is:
Rebuilt alternator and dizzy (why I thought it might be a ignition problem)
New airfilter
New oilcooler
Removed the viscous fan
Changed all the pullies to light weight

Other mods to the engine is
TRD cams 272º 7,5mm
TRD Pistons
TRD 0,8mm gasket
Stainless header and exhaust

I'm really lost on what to do next. Buy new Sparkplugs, wires and dizzy cap? I'm thinking of doing a compression test on it aslo.

// Johan

[bozu]

I can't make it up clearly from your post but did you change the pistons and the headgasket etc as well over the winter? or only the alternator, dizzy etc?

[totta Crolla]

It is possible to put the distributor drive back onto its shaft 180 degrees out after you have rebuilt the distributor.
You mention light weight pulleys ?
If you have not changed the crank pulley then it would be a good idea
to check the TDC reference is correct, the outer rim has a habit of
turning independantly of the inner part. When this happens your TDC
marks also move and your ignition timing will be out even though
it appears to be at 10 degrees when timed with a light.

[krullibull]

bozu Wrote:I can't make it up clearly from your post but did you change the pistons and the headgasket etc as well over the winter? or only the alternator, dizzy etc?

Only the alternator, dizzy etc.

totta Crolla Wrote:It is possible to put the distributor drive back onto its shaft 180 degrees out after you have rebuilt the distributor.
You mention light weight pulleys ?
If you have not changed the crank pulley then it would be a good idea
to check the TDC reference is correct, the outer rim has a habit of
turning independantly of the inner part. When this happens your TDC
marks also move and your ignition timing will be out even though
it appears to be at 10 degrees when timed with a light.

Hmm, how do you check if the drive is in the correct place? The crank pulley has been changed as well.

[Ivan141]

Ordinarily you could do the following things to make sure everything is set correctly @ TDC:

-Set crankpulley to 0 deg mark
-Check for dimple in camshaft under oil filler cap (not an option on aftermarket stuff probably).
-Take out nr1 sparkplug, use a long screwdriver or whatever and feel if the nr1 piston is really at TDC.
-Take out distributor @ top dead center. If you have it in correctly, there should be a line on the shaft that lines up to a dimple on the body directly above the shaft on the distributor ( or was it vice versa, anyhow you get the point).

-When you're sure piston nr1 is really at TDC, check campulley positions.

[allencr]

What's the compression?
Set the timing so it runs well, high fast smooth idle. Forget the timing light, toss it except for checking that the advance works & passing emissions! Advance it until it only pings/detonates when abused, with the octane of your choice.
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**
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Advance is the ignition advance, 10-15 at idle, going up to 30 @3000rpm or there abouts, that's what really counts

The advance with the diagnostic plug means nothing at all, except for the diagnostic plug. I wouldn't care a bit about it.

[krullibull]

Ivan141 Wrote:Ordinarily you could do the following things to make sure everything is set correctly @ TDC:

-Set crankpulley to 0 deg mark
-Check for dimple in camshaft under oil filler cap (not an option on aftermarket stuff probably).
-Take out nr1 sparkplug, use a long screwdriver or whatever and feel if the nr1 piston is really at TDC.
-Take out distributor @ top dead center. If you have it in correctly, there should be a line on the shaft that lines up to a dimple on the body directly above the shaft on the distributor ( or was it vice versa, anyhow you get the point).

-When you're sure piston nr1 is really at TDC, check campulley positions.

All three marks are where they're supposed to be when the piston is at TDC. I will remove the distributor and check how it lines up.

allencr Wrote:What's the compression?
Set the timing so it runs well, high fast smooth idle. Forget the timing light, toss it except for checking that the advance works & passing emissions! Advance it until it only pings/detonates when abused, with the octane of your choice.

As it is now it idles at ~800-900RPM when hot. Now that you mention it, I'm not really sure the car advances the timing when the diagnostic is pulled out and emissions is not really anything I need to worry about, I'm allowed to have 4,5 CO . Don't have any chance to get a compression test done until 2 weeks or so .

Another thing that I thought of but it seems like a real long shot or maybe abit retarded is that the oil is to thick?

So my to-do list for Sunday so far (only chance I have to work on the car this week) is:

1. Check that the distributor lines up.
2. Try and advance the timing some more but 15 degrees BTDC seems really high already.
3. Spray startergas around the intake and vaccum hoses to check for leaks.
4. Some injectorcleaner?
5. ???


Thanks for all your help so far!

// Johan

[Bean]

if your car doesn't go into diagnostic mode (search the forum, plenty of threads explaining it in detail) the timing needs to be set at 16° BTDC when warm (@~800rpm)

for the oil to be too thick to get your symptoms the bearings would have seized long ago

[fax0815]

2 pretty obvious things:

Have you checked for diagnosis codes on the dashlight? Does your car go into diagnosis mode as soon as you shortcut the terminals? (idle drop, changing the timing, flashing light on dashbord)

Checked the cambelt? Did you dial in the cams in according to the spec sheet? I had it once wrong by one tooth exhaust cam and the throttle response was awfull so was the poweroutput.

Don´t think there are any air leaks cause the idle is perfect. I also doubt its fuelrelated, but an injection clean doesn´t hurt
No chance its the thick oil!

[Ivan141]

Did you check if piston 1 was @TDC physically? It's not unimaginable to get this wrong when changing pulleys. The crank spins twice for every turn of a camshaft.. so there is the possibility of getting things wrong when reassembling.

Oh and another check, you'll think I'm insulting you but I got this wrong myself once: You sure you got the order of your sparkplug wires correct? You're symptoms sound mighty familiar....