16valver

I finally did some official calculations on my gas mileage. The results weren't pretty.

I did one run before I replaced my vacuum lines and got 12.8 MPG city and hwy combined.

I did another run after replacing the vacuum lines w/venturi delete + driving like a grandpa and clocked in yesterday at 13.8 MPG.

Things done to the fuel system recently:
-FPR replaced
-Injectors witchhunterd'd
-FPR and FPD vac lines replaced
-Fuel filter replaced
-O2 sensor replaced
-LR fuel lines under the hood (not that it would make a difference...)
-Stock Cat, stock resonator (I think) and a flowmaster 50 delta flow 2.5inch in and out

I have a starting problem that seems to be solved by pumping the gas pedal when it is struggling to turn over. I also still have the enigmatic squeaking noise happen every once in a while (less with the warm weather). I have no idea if this stuff is related but I feel it very well could be. Here is a video of both those symptoms:

I need ideas on what could possibly be going on here. My uncle suggested I try and pull my reference sensor(s) to see what kind of shape they're in. I'm also wondering if bad knock sensors could do something to my timing.

Maybe the filter in the sending unit?

Arominus suggested I try gutting the cat to see if it makes a difference. I will probably go down this route as well just to see what happens.

Car runs great but the idle is sort of lopey. It will sometimes backfire when I rev-match on a downshift.

Lemme know what you all think.

VirginiaF1

Good vid, is it that hard to start EVERY time lately?

Fuel pump is factory original?

16valver

The starting issue goes like this: if the car has sat for a night or and everything is cooled off, it will fire right up. Its when things have been warm that it doesn't like to start. BUT, when the car has warmed up to operating temperature, then cools off a little bit if parked for an hour or two it still fires right up. Sort of an odd thing...

Thanks for reminding me, I forgot to mention that the pump was replaced in 2004. I'll get under there and look at it soon to see if its a high volume pump or something.

I also forgot to mention that the needle valve on the AFM has been tampered with. I found the cover off when I got the car, I closed the valve all the way and opened it 1.5 turns to get it close to factory spec. I definitely get the feeling that it is a contributor still, though.

VirginiaF1

DME/Fuel Pump Relay original?
http://www.clarks-garage.com/shop-ma....htm#hot-start

carlege

wonder if your AFM is on its way out.

Arominus

The resonator is factory on the 16v cars, and if the afm has been messed with... you could be all out of whack for sure. Try to get an S/S2 afm that hasn't been molested?

Jamesr6967

Sounds to me like it is too rich. Check your coolant temperature sensor wiring inside the boot at the connector and your air temperature sensor on the AFM. Mine was running rich and was difficult to start when hot. Mine turned out to be the wires inside the coolant temp sensor boot.

A.M.H

All of the above is/would be good things to check. However, the very second I read that you still have an OE cat, immediately I thought, you need to get rid of it. Replace with a High flow cat. I can almost guarantee that if it is clogged, it will cause a plethora of run-ability problems, similar to what you are experiencing.

Also, most likely directly related, is your AFM adjustment needle. Not sure how the correct process is of adjusting those, but if they "in essence" work at all like the needle valving for a carburetor, cant you just adjust it while the car is running, and while operating the throttle by hand at the TB by revving it every couple seconds to see/feel the response, get it close to a normal, or better running condition? I've never messed with mine, and dont want to.

Also, just to throw out there, that when an ignition coil is on its way out, the same type of symptoms will occur. When they get hot and up to temp, if you shut the car off, and then try to start with in the first couple hours, they wont send strong enough, or consistent enough spark. However, if completely cooled off, as in more than a couple hours of off time, it works just fine. This happened to me with a Honda. Traced EVERYTHING to figure why my car would start when cold, but not when hot. Same scenario. I replaced all sorts of crap. Fuel pump relay. Fuel pump, Fuel filter, TPS, etc. while still having the same problem. Got so bad that one day while I was driving, out of no where, the car just dies. It was a 5 spd. Not even compression would keep it running. Ya, turned out it was the coil going out the whole time. Never would have thought.

Anyways, hope you get this figured out man

Ben951S

Cheap and easy. Ready?

Fuel Pump (DME) Relay - Should have a spare, get a new one and put it in and keep existing as spare
FQS Switch - Should apply to NAs I think too, take a look and make sure it's in the right spot
New Crank/Ref sensors - Facet E30 or or 5-series parts, like $35 each from Pelican or elsewhere [easy to install if originals not 'stuck']

Lastly, maybe I missed it, has it been like this since owning the car? It could be the AFM or something uglier as suggested, but I like my list first!

Arominus

Remember that the 16v motors have the combined crank reference sensor. Don't know if that effects which parts you need.

Ben951S

Learned something new today.

carlege

You can also isolate the problem by jumping the fuel relay making sure it gets gas... Then gas shouldnt be an issue. If its spark related a noid light should help you determine that. I urge you to trouble shoot a little further rather than throwing parts at the problem. But thats just the starting issue. The MPG problem might be a whole other problem. TPS could also be a problem along with the AFM

16valver

SOOOO much good stuff!!! Thanks guys!!!

I have an idea that the afm is on its way out (HURRY UP ROUGE )

The coil looks original. That could very well be the issue.

The symptoms for bad DME fuel pump relay seem slightly different than what I'm getting. Cold starts are fine, hot starts are fine, after the car has sat for a good 3-4 hours its no bueno. Its almost like it wants to run hot start settings when its cold or something. DME isn't out of the question though. I'll try grab one to throw in there soon.

I agree, the cat needs to go. I'll try and find a high flow one.

I'm interested in this jumping of the fuel relay. When I have some time I'll do the clarks procedure and see what I get.

Will Feather

I was thinking this also. Deff cut the cat out ASAP, need one for your state? If not just straight pipe it.

Arominus

Just looked it up, the 16v motor uses the same reference sensor as the 8v, it just uses 1 instead of 2. Why? the 16v cars have a hall sensor up at the front of the cam for positional data. I doubt that either of these is your issue though, when the wiring to the Hall sensor in my S was acting up, the car would just die and then not run at all until the wiring cooled (the mount had broken and they were really close to the exhaust).