Possible timing issue?

[G. White]

All right guys here's my situation. I will describe everything as accurately as possible. Here goes-In the morning while my engine is still cold, I get a pretty good hesitation (no backfiring) almost feels like Im towing something heavy in the low rpm range. Once the engine revs over 3500 rpm's it wants to take off like a raped ape. However, once the engine warms up to normal operating temp acceleration is normal.
2.0 lxi fuel injected

So far I have changed

Plugs ( they are gapped properly)
Plug wires
Fuel Filter
Air Filter
Distributor cap and rotor
I pulled off the EGR and it is clean (so are the ports) and working properly
New battery
I swapped ignition coils and it still does same thing
Checked/regapped int/exh valves
No blinking lights on the ECU
Clutch doesn't slip at all

The only things I can think of is possibly the fuel pump might be going bad, but wouldn't the car bog down at higher rpms because of a lack of being able to supply fuel?
Coolant temp sensor?
IACV?
Bad injector?
O2 sensors only come on when the engine reaches a certain temp if I'm right so that wouldn't explain my cold operation snafu.
I checked the gaps on my intake and exhaust valves and the exhaust side was gapped too tight. While I was doing that I noticed the timing belt looked fairly new.
Could it be possible that the timing belt was installed a couple of teeth off by the previous owner?
Any input would be greatly appreciated. Thanks in advance.

[EricW]

If the timing belt was off it probably wouldn't run. Its an easy check though. Turn the crank TDC, where the pointer is pointed at the T on the flywheel or flexplate. Then look at the cam gear and see if the up mark on the cam gear is facing up like it should be.

[Dr_Snooz]

Run some Techron through it.

[Oldblueaccord]

Mileage?

is the motor tired or using oil?


wp

[nswst8]

I like PB blaster fuel injector cleaner. (Carquest, NAPA, Western auto) Or BG 44K is the latest rage most Auto PX will carry BG products. Its where I get mine.

IACV is a easy clean, I'd recommend it.

Fuel pressure is the next thing to check, Faulty gas cap would be the 1st fix. Do you get a pressure release after opening the gas cap?

What is the idle like, an adjustment might be in order.

[2oodoor]

wow what a list, but it doesnt include checking the ignition timing. Whoever installed the belt should also recheck the ignition timing in case it was adjusted to compensate for the other belt being a tooth off.
Kinda sounds like it too because if the thermo vaccum switch doesnt let the the second vacuum advance work until it is warmed up good.
Retarded ignition timing would let the car run good at higher rpm but at lower rpm it would be like pulling a lead sled.
Im not talking about it being a whole lot off, just a bit and that is all it takes to produce these symptoms.
Just my thoughts on it. oh yea and BG 44k is some really good stuff.

[Oldblueaccord]

Roodoo I was thinking the same. Vacuum advance when cold not advancing like it should. Test out the vacuum advance.


wp

[w261w261]

Awhile ago, I had pretty much the same symptoms you are describing. When cold, not so good until 3500, then ok. Pardon my relative ignorance here, but I think there is a secondary that opens up at that rpm, which produces a nice kick in any case.

Turns out I had a failing TW sensor (coolant sensor) and a failing distributor. Since they were both replaced at about the same time, I can't say which did the trick, but afterwards things were good.

[Dr_Snooz]

Hmmm...

Okay, my distributor is getting tired. The vacuum advance mechanism was well out of tolerance and I wasn't getting anything like you describe. What I noticed most of all was a weird electrical cut-out and bouncing tach needle while cranking each morning. Yesterday, I did a half-assed overhaul for which I'll do a write-up shortly. Anyway, what I'm noticing today is no more electrical cut-out. Also, throttle uptake from stops seems to be a lot better. I used to press the gas pedal slightly and wait for the ignition system to catch up before accelerating further. That's all gone. Finally, the idle is a lot smoother. (Disclaimer: these observations are based on one drive after the overhaul and are subject to change).

Couple thoughts:
- TW sensor should flash a check engine light. A bad TW sensor gave me a CEL and a hard warm start issue.
- It could be a distributor issue, but I doubt it.
- I suspect you have a dirty fuel delivery system, but it's worth proceeding through the diagnostic portions of the manual to see what shape your timing controls are in along with your TW sensor. You can do that for free. You'll need a timing light, vacuum pump and volt/ohmmeter.
- I wouldn't drive a 20 year old car that hard while it's cold. Wait for it to warm up and then get on it. Better yet, just be gentle all the time...
- If it weren't a dirty fuel system, I'd still say it's a dirty fuel system and tell you to keep running premium Chevron. I've been running my sticky valves on Chevron premium for the last 2,000 miles and the idle is only slightly less rough.
- If you drove 20,000 miles on premium Chevron and the issue remained unchanged, I'd suspect it's a sensor of some sort, but again, you'd get a CEL.
- A can of Techron runs about $8 last I bought one and it's a cheap, easy test. If things get better, you kinda know it's a dirt issue. If not, come back and we can proceed from there.

Sorry that's so long. Anyway, keep us posted.

[Dr_Snooz]

Here's the write-up. It definitely wouldn't hurt anything to do this:

Lazy man's distributor overhaul (http://www.3geez.com/forum/showthread.php?t=66468)

[G. White]

Mileage?

is the motor tired or using oil?


wp

The engine has 160k mi and doesn't burn any oil. The plugs look good and do not have any evidence of oil fouling.

I pulled the IACV off last night and took a look at it. The little screen had a tiny bit of buildup but nothing considerable. I cleaned the whole unit with electric cleaner. It made a little bit of difference. The car wasn't so hesitant on the way to work today.

It's ironic that people would bring up distributor issues. Just today for the first time I had a couple of strange things happen. One start up I had today I could swear the tach bounced. I had another where the dash lights sort of dimmed and it sounded like the starter had issues. Keep in mind the battery is brand new and the charging system has always worked well.

What is the proper procedure for timing the crank, cam and dist? I take it I will need to go back and verify the valve clearances afterwards.

I will also look into the TW sensor. These are all things that I should change out just due to the age of the vehicle.

Thanks for the input everyone and I will keep everyone posted.

[nswst8]

Did you clean the coolant chamber on the bottom of the IACV.

Timing TDC, just under the the dizzy on the transmission housing you will see a vertical retangle shaped sitehole, that will give you the ability to see the flywheel.

On that flywheel there will be a tipped over T that should be centered on the pointer. (Rotate the engine counter clockwise) This is TDC.

If you want to remove the valve cover there are two horizontal hash marks on the backside of the cam that will level out with the cylinder head top edge.

At the front of the cam at the 12 O'clock position you will see the word "UP" This is 90 degrees to the hash mark.

As you adjust the valves you will rotate the cam 1/4 turn per cylinder.

[G. White]

Did you clean the coolant chamber on the bottom of the IACV.

Coolant chamber was clean.

I think the plan of attack for this weekend will be;

1. TW sensor
2. Re-time engine
3. Poor mans dizzy rebuild

If that doesn't work

1. Check fuel pressure/ possibly replace fuel pump
2. Get fuel injectors flow/bench checked for serviceability

If that doesn't work
:burn:

[Dr_Snooz]

If that doesn't work
:burn:

Yeah, or you could always try that can of Techron...

[Demon1024]

adding a couple of new grounds can't hurt either. you starting issue made me think of it.bad grounds can make these cars do funny things

[nswst8]

Yeah, or you could always try that can of Techron...

You have stock in Techron, admit it:bandit:

[Dr_Snooz]

You have stock in Techron, admit it:bandit:

Ha! Just call me Mr. Rockefeller...