Timing was checked to third gens timing guide, now am I right in thinking my timing is set to about 2 degrees a dance in timing?

Hope you can tell from the picture...



If you can't tell, it's just after the big V cut out,but before the little v cut outs.

Any help would be appreiated, as my car has a fueling problem and I'm struggling to find it. (6mpg, uk gallons) ).

 

I see two lines so not sure. If this is a TBI set up the timing spec is 0* BTDC. If this is a TPI set up the timing spec is 6* BTDC. Be sure to do this with the engine warmed up and the EST/BYPASS connector open.

The center of the wide V is 0*.

RBob.

 

Hopefully that picture is better.

From what I've read it's best to advance the timing by 8-12 degrees to help performance with the car, Which makes perfect sense.

And yes it's tbi, that drawing is quite hard to see on the phone, will have a look at it on pc when home.

 

Its fine where its at! LEAVE THE TIMING ALONE! 2 degrees either way that close to 0 or tdc is not gonna make much difference if any! Maybe try to explain a little better what type of problem you are having!

 

Here is a real timing scale for thirdgen's. LOOk

 

Your timing looks to be at 2 degrees BTDC

 

Ahh that's all I wanted to know, just to make sure i was reading it right.
Symptoms it has are:

-High fuel consumption (12mpg)

-Sometimes stays at high rev, can be driving along or stationary and revs can stay at either 2K, 3k 3.5k of revs ( although that's taco reading, which is dodgy anyway). But you can tell its revving high.

-Smell of unburnt fuel on idle

-Sometimes hunts when cold or just been started from stand still after being off for 20 mins.

Things I've checked:

-Timing ( seems ok)

-Air leaks ( again seems ok, couldn't find any leaking pipes)

-Tested the coolant sensor, but on at the sensor and not the ecu side yet.

-injectors aren't leaking either

So if anyone has any other ideas, please say?

 

yes you can advance your timing if you like. In some cases it does make a difference just make sure you know what you are doing or you may cause engine damage. If you have never messed with the timing before and this problem has just occured then it is probly not in the timing if the distributor is not loose etc. Just trying to keep you from wasting a ton of time somewhere that the problem may or may not be!

 

If its tbi you should be getting some type of trouble codes! Find out what they are!

 

I understand timing and problems with pinking etc if too far.
Messed about with it when I first got it as it was wrong, but that was over 6 months ago, so maybe we just set it to 0degrees.

Just trying to find the main fuel consumption problem now.
Along with trying to find somewhere in the uk to buy full weather strip seal kit with out being ripped off.

I've done the blink test and no codes.
Building an Aldl cable as we speak so I can read ecu on the laptop.

 

Check the grounds, esp the ecm grounds, might be at the t stat or back of the heads.
Is the engine running cool? A bad t stat (sticking open) can cause bad mileage.
I'd check the fuel pressure, it might have a restriction in the return line, causing high pressure. Stock spec is 9-13psi.
How did you check the cts? Resistense using a multimeter? I'd check it in a pan of hot water (200 degrees). Is there an air inlet temp sensor? Check that too.

 

Did you check the base timing with the timing wire (temporarily) disconnected? Have to do it that way or the timing will be very retarded under actual operating conditions.

 

If you hold it steady in park at 2000rpm with the set timing connector disconnected, the time mark should also be steady. If it's not you have a problem in the distributor/timing gears. I would suspect the distributor.

 

If the timing mark bounces around it means that there is play in the timing chain(wore out) I doubt it though. Being a computer controlled car it would run like absolute crap!

 

Crankshaft Test for chain stretch; EHow.com
If you don't have a degree wheel make the marks on the balancer then measure the distance between the 2 marks this is the slack. Find the circumference of the balancer and divide by 360, this is the length around the balancer for 1 degree in inches then divide the chain slack measurement by the 1 degree length to convert to degrees.

 

Coolant sensor was measured with a multimeter and checked to see if it increased/ decreased in resistance as it got hot.

Engine temperature opens at optimal range( 230f on the gauge I think it is).

Can't see it being fuel pressure I haven't checked as the idle raises, although will look into it to make sure.

Can't see it being inlet air temp as it measure inlet air temp? Doesn't have much of affect on fuel?


Timing isn't bouncing about, and the little tan wire leading I the green/black stripe wire was disconnected.

Now when altering the timing, do you alter it while the wire is disconnected or when it's connected?

 

Tried coolant sensor with different multimeter and turns out my old one was fault. Coolant sensor is ****ed, has no connection when measuring them. Thanks for your help guys.

Now just the other two problems I need solving lol.

 

Set timing with it disconnected or else the ECM will try to adjust the timing to compensate your adjustment.
If the Sensor was open there should have been a code 14 or 15.

 

Sounds like you found at least part of your problem. The CTS sensor. If it's reading full-cold (-40F, bottom of the range) it won't go into closed loop. Gotta be at about 100*F or above for that to happen.

I have to say that I prefer to see things the way the ECM sees them- not just measuring resistance across a sensor, but seeing what the ECM interprets those signals to mean real-time. I.e. use a scan too and see what the ECM thinks the coolant temp is. Just an old habit of mine when working on computer-controlled cars.

I had a TBI engine once that would occasionally throw a code for too high a CTS reading. CTS tested OK, but I replaced it anyway, to no avail. Eventually, with the help of a scan tool, I saw it would sometimes click up to 265* for no particular reason. Something about the behavior told me "this is an intermittent short". Traced thw wires back and found they had popped out of the wiring loom and rubbed themselves raw against the edge of a bracket- must have taken THOUSANDS of miles of driving to do so. Fixed the wires and never had a problem again.

Agreed with above, you check and change base timing with the timing wire disconnected. Plug it back in after you're done.

 

I didn't know about that, we checked it at about 7c degrees, so it wouldn't of been a closed loop at that time. Got a new sensor, put it on and the car runs more ruff now than it did before. So must been given the wrong sensor.

Only code I have on the blink test is code 12, est connector to dizzy is faulty? which is normal when car isn't running, isn't it?


Built my scanning cable, downloaded winaldl and turner pro rt to do some data loggin and scanning. So hopefully get abit of a better insight soon.

Thanks for your help sofar.

 

Got my Aldl Cable working and recorded some datalogs, anyone care to have alook and point out anything that is out of place?

Retested coolant temputure at about 90C degrees and it was working, it seemed to read fine when warming up to?

 

download TTS Datamaster and use that.

 

have you changed the map sensor? i also have a TBI and suddenly my car got 12 mpg (which wasnt good considering our income was about 150 every 2 weeks...) my father-in-law told me to change the map sensor (since he was the one who rebuilt the engine) and sure enough my fuel problem went away and got back to my usual 20-22

 

Can't get TTs datamaster to work, tried different version with the 10k resistor aswell and nothing.

Replaced map as that was reading at 0.9v and from what I found it should be 1.2, at which the new map sensor does read at.

Still has random high idles, stinks of fuel on idle aswell.
Notice it's idling at 600-650 rpm aswell, I assume it should be higher?

 

both of my 3rdgens have always idled between 500-700 so i think thats fine

 

That's good to know, will double check the manual to make sure.

This is the car on idle seems the winaldl doesn't save sensor reading properly.

 

Nothing looks out of the ordinary in that screen shot to me other than you might have a vacuum leak. I would look at a worn/sticking IAC, blown TBI base gasket, a bad EGR valve or perhaps even a catalytic converter that is plugging up.

 

Definitely not cat, as it hasn't got one lol.
If egr then all the smog control shall be coming off. Will check it tomorrow.
IAC looks to be workin correctly?
Tbi gasket might be something, will take air filter off and have a look round.

 

The reason I say IAC or vacuum leak is it looks like its commanding 1 count. Normal specification is anywhere from 15-50 IIRC.

 

I'm with Fast355 on that one. Wouldn't be the first TBI engine with a vacuum leak. I had an old GMC Jimmy with a similar 4.3L V6 TBI engine. Idle and light throttle just wouldn't behave. Turned out the factory PCV line (hard line) from the TB to the PCV valve had a big split in it- on the underside where you couldn't see it. Replaced with some parts store 3/8" vacuum line and the thing ran another 3 years flawlessly until I sold it.

 

Right think I've sorted it now.
Iac was actually lose, so took it off cleaned it, and actually tightened it up.
Replaced the map.
Advanced the timing to 10% and now the car idles perfectly and drives lovely.

Thanks for your help folks.