davila0115

To check the FPR do you just unscrew all those torx security screws?... is it under pressure?

To get the injectors checked / cleaned its gunna be 65$ and the FPR is like another 60$... kinda alot of money on whims..

davila0115

WHOOPS DOUBLE POST....sry

willexoIX

Pulled the injectors from a 1996 buick century custom with the 3100 SFI V6. My original injectors were pintle style and 22 years old when I pulled them. Yes it runs rich, but mostly only when im ON the gas. I was getting right around 13-15mpg with the original injectors. right around 25mpg with the buick injectors, and the buick injectors are disc and rated at 18lb/hr; unless I found bad info.

The car runs 1000000000000 times better with the buick injectors in it, smooth idle, great response, and yes my plugs wind up being flat black a little bit, but i clean and gap them quite often. I try to take meticulous care of my car, but I kid you not when I tell you I get right around 25mpg sometimes better.

Now that I think about it, doesnt the computer attempt to compensate for the extra fuel? But not sure about that one, let me know

BTW, Im running a 180* t-stat and Actual cold air intake, new timing set, bosch platinum plugs, hollowed cat with a thrush welded turbo muffler. Thats just what I remember, lol

Base91

iTrader: (1)

FPR is under pressure so before removing top or injectors you need to use the inspection valve to de-pressurize. Use plenty of rags to soak up the gas that leak out when you open the rail and make sure you keep it totally clean. Spending money is unfortunate but unless you find a specific culprit for the problems you have to check/replace as required. If you get your mileage back up to nearer 20mpg it'll pay for itself pretty quickly. These aren't whims, these are the things that are likely to be defective on a 20 plus year old car.

ex-x-fire

If the regulator passed the psi & pressure leak down test, theres no reason to change it.
I'd check the ignition timing & make sure it advances when rev it. Retarded timing causes low engine vacuum, which the map sensor picks up & tells the ecm to richen it up.
Check the ecm grounds too.

Maverick H1L

iTrader: (8)

MAP is tested with the key on as that's the only time it gets power from the ECM (the gray wire is the +5V reference voltage source).

beleneagle

I think I've figured mine out. I have exhaust leaks due to the PO high centering the car and pulling the exhaust to the rear. I'm thinking that the leaks are making the O2 sensors read lean, and therefore causing the puter to richen the mixture. I gabbed a cherry y pipe off of a 91' S-10 2.8 that I'm going to use/modify to the car. It dumps into 2 1/2" single and heads straight back to the cat. I'll need to pick up a 90 degree elbow to fit that set up to the Camaro.

davila0115

So i finally got a new timing light, and checked the timing. I never mentioned i dont think that when i did the cap and rotor, that the previous owner stripped out the cap screws pretty good.. new cap wouldnt come near to tighting down. So we bought a reman and put it in. We marked the relation of everything and got it pretty close to how it was before... but didnt have a light to double check it.. well i just checked it and it was at about 3deg btdc.... ya i would say it was retarded.. ha.. i set it to 12deg btdc. the car had much better pickup in a short 1/2 mile drive i tested it...

I plugged that est wire or whatever its called (TAN) back in. and then checked the timing again, it was around 24?... and when reved advanced more...

in the past i was told i could reset the ECM by pulling the fuse on the pass fender and that would kill power to the ECM. is this true? last time i did it i didnt have to do an idle relearn again. so idk if it worked or not.

willexoIX

When you unplug the EST (tan) wire, it will allow you to set the timing. As soon as you plug it back in, the computer will automatically retard or advance the timing depending on the operating conditions, eg, acceleration, deceleration, so on and so forth. So when you plug the EST wire back in, yes your timing will jump all over the place, after all EST stands for Electronic Spark Timing

I would take the negative terminal off the battery to do a reset, and let the computer do a relearn after the timing was reset as well, but thats just me.

davila0115

Well ya i assumed it would advance and or move around.. figuring thats why you should unplug it to set the mechanical timing. But can i reset the ECM by just pulling that fuse? or do i have to pull the battery and reset all my audio stuff? haha

willexoIX

I know what you mean about the audio settings, everytime I do it I have to reset my presets and everything else, but I do the negative disconnect anyway.

I'm pretty sure if you pull the ECM fuse, it should reset it. Cause your cutting the power to it, it should reset without you having to pull the battery cable.
I could be wrong.

davila0115

Just thinking.. around the house i have what i think is about 24 ga and some 16 ga steel. Obviously the 24 ga steel is much much easier to cut and shape. But do you think the 24ga will be thick enough for the egr block off plate by the TB?

Now that i know the timing is fixed. i want to see if that was the MPG problem. So i am going to fill up soon, run a hundred miles or so, and check again. Then block off the EGR and see if it gets better... Thoughts?

willexoIX

Process of elimination, I wouldn't block off the egr until after you run the car to find out if it was the timing or something else.

joecool108

yes my car is a 3.1, 5 speed with headers, no cat, no egr, new timing chain, new distributor, new head gaskets, no smog equipment, only the pump remains because I cant figue out how to eliminate it yet. Injectors are about 6 months old bought from Fuel Injection Connection in Atlanta - Guy gives great service, new fuel pump, new wires and plugs.. car still gets crappy mileage. Installed new heated O2 sensor because of location in headers. My V8 gets better mileage! Maybe I need the computer reprogrammed because the EGR is gone and smog stuff is gone?

davila0115

Well just a recap for now.. Again i appreciate all the help from everyone!...

I have replaced in the past month
-02 sensor
-new starter
-new oil pan and gasket and fresh oil
-pcv valve
-cap, rotor, plugs, and wires
-IAC
-Air filter


I have also Checked:
Timing - Was low set to 11-12deg
Set idle Air - after changing the IAC everything acted wierd so i check/fixed
Checked fuel pressure - held pressure for over 30 mins @ 38psi +

These are things i need to check:
-Injectors? Fuel pressure test was good..
-FPR? Fuel pressure test was good..
-Block EGR
-IGN coil? Old plugs were Bosch plat +4 looked a lil black? I'll post picture
-ECM ground. Are these the ground straps from the firewall to the engine? I can only see one from the firewall to one of the upper intake bolts?
-Test Map sensor? I still do not know how to accomplish this...

Waiting for a few more miles on the car with all the new parts so i can fill up and check mileage. Is there anyway that my datalogging can help me diagnose? Thanks again for everything...

ex-x-fire

Is the engine running cool? It should be running at the middle of the gauge, 195* stat is stock, cooler temps greatly affect mpg.
Check the cts resistence.
Check ecm grounds.

davila0115

I know that generally the gauge is around the line that is in between the 100 and 220 marks?... i also know that once the engine is fully fully warmed up to where the fan comes on the gauge is at around 240 deg. and the engine temp (IR THEMO) is around 220. so I am unsure if the gauge is always +20 deg or not. but i since the gauge shows 100 - LINE - 220 - then 260. is the line between 100 and 220 supposed to be 160deg? thanks.

thebuffalo

10mpg on a v6? Swap a v8 in it. Should fix that problem real quick.

For your temperature issue, get a new thermostat, you shouldnt be having your fan turn on at 220, more like 190-200.
I have mine hardwired in so... it's always on.

davila0115

if the thermostat was bad wouldn't the top radiator hose always be hard? (assuming it failed open which i kno the factory orig didn't.) or is it bad bc it has to get extra hot to open?... and either way the CTS is new. the cts is going to see what temp the engine is whether or not the thermostat is open or closed.. its just going to take a lot longer to heat up if its stuck open right?...

Maverick H1L

iTrader: (8)

well, buffalo is wrong... The fan turns on at 235 stock, whether it's by the fan switch or the ECM (fan switch on 2.8 cars).

Guys, I was getting 27 MPG highway with no smog pump and no EGR, and junk fuel injectors that either leaked or were shorted or both (EGR solenoid was defective at the time), so no, those aren't going to help your problem just by removing them or blocking them off. Unless the EGR solenoid is leaking, of course.

Check the CTS. Check the MAP output. Check the TPS output (TPS reading too high can force the ECM to put too much fuel in the mix for the throttle position). Check the IAT in the air box (the CTS and IAT should be pretty close to the same temp if the engine is cold). Check the fuel injector resistance on EVERY injector and toss any that are below 11.8 ohms. And check your RUNNING fuel pressure. Should be no less than 37 PSI and no more than 47. And check your overall engine vacuum... Probably at the cruise control servo would be best.

davila0115

I have replaced the CTS, I just know the gauge is off. Need procedure to check the TPS and MAP. Obviously key on, but measurements? ranges, values?.. The IAT is clean, idk value yet. Injectors and FPR i am waiting to do until after the EGR block test. And the running fuel pressure is @ 38 psi. What vaccum reading am i looking for?

Thanks

KrisW

iTrader: (5)

All of the readings you need to check are in the Chilton's repair manual (or the Haynes manual.)

Do block the EGR. Just use a Beer can and make it 2 or 3 layers, right up at the intake part where its easy to get to.

After I did mine (on my 248k 1990 3.1 'Bird) I was nearly 30 mpg on the highway. My EGR was internally stuck open partially and just pouring in the crap at all engine speeds. I'm sure a new digital EGR would have been great, but it was almost 300 bucks when I was doing it back in 2001. I was running used 1988 2.8 injectors, too.

Another time, my ignition coil was shorted through the middle and at night you could see a spark jump from the coil to the mount bracket. It got so bad that eventually it wouldn't start. Just more thoughts...

Don't give up!

ex-x-fire

Your looking for a vacuum reading that 17" or higher at idle, w/ a smooth needle.
If the t stat is stuck open the engine will run cool, the cts doesn't operate the gauge, it tells the ecm the coolant temp, the ecm takes the info it gets to determine the injector pulse widths. The cts takes the place of a choke on a carbed engine. If your temp gauge takes a while to get up & is still low, I'd put a 195* stat in it.

Maverick H1L

iTrader: (8)

Just because you replaced the CTS doesn't make it any good...

Vacuum reading should be about 15" and be steady (use a decent gauge and not one on a MityVac or something like that).

Others I need to look up...

davila0115

Something that i found interesting this week, There was an unusually warm day for us up here in NWI, and i had the windows down, when i rolled them up and when u get to the top and they top, when u press the buttom to close them more, obviously binding the window motors, drawing alot of amps, the engine rpm goes down like 100 rpm or more... then i realized it did the same with the subwoofers on full blast.... i have never had a car do that before?.... bad grounds or coil going out?... amperage draw away from the coil or ecm making it not happy? just a thought.. haha. Thanks.

davila0115

So I finally got the Coolant leak taken care of... i also figured that since every other ignition component is new, i would change out the coil. delco was about 5$ more than the MSD coil.. so i got the MSD. all installed went well.

I also had the chance to put a clear hose on the FPR and pull a little vaccumm to see if fuel would come though the line. Nothing came through.. so i think thats a good sign.

I went on a 80 mile highway trip last weekend and and on one take of gas, i had 80 miles city and 80 miles highway. and the overall mpg was 16.5 MPG... not bad i guess. So idk exactly what city and highway miles are still... lol I got the injectors left to do.. just waiting for the gaskets to come in..

Firebird_305

One of the posts mentioned above relates to the EGR and blocking it off. It being stuck open being a reason for poor fuel mileage. To test this out, could you disconnect the EGR, but leave everything hooked up (i.e. connected to the intake and exhaust)? Then if mpg go up you could block it off and if it goes down you could connect it again? Want to make sure I'm on the right track.

Maverick H1L

iTrader: (8)

If one of the ports on the digital EGR valve is clogged open, disconnecting it isn't going to do a thing. The thing is built in such a way that it is indeed pretty easy for the pintles to get clogged and stuck bad within the solenoid chambers (not much clearance). Only way you can check to see if it's leaking is to pull the intake end off of the intake, plug the hole in the intake (with a cork or something), and run the engine to see if exhaust comes through.

The valve can be cleaned, but it's super easy to break the tiny screws holding it together at the base due to the repeated heating and cooling cycles along with corrosion from water vapor in the air and what not.

:edit: And, trust me, if the digital EGR valve was stuck open at idle, you would know. The engine runs like real garbage with the EGR open at idle. Tested the EGR on my 93 Grand Prix at idle (kept getting a code 32 I never figured out how to fix), opened all 3 pintles with a 9V battery, and you could easily tell when each pintle opened because the engine would stumble like crazy. Oh, and it would be very hard to start.

Firebird_305

Hmmm okay then, just trying to think of things that would cause poor mileage. haha! Why do people to the egr delete then? I've contemplated it before, but never any solid evidence to do it.

Maverick H1L

iTrader: (8)

Well, I'm sure you've noticed the thick black carbon coating on everything between the throttle plate and the tailpipes. EGR delete gets rid of the intake side of that, which keeps ported and polished intake surfaces cleaner (may help with the exhaust side of it on other engines, but the 60* is designed to run rich). It also keeps the exhaust out of the cylinders and leaves more room for the stuff that actually goes BANG .

Firebird_305

That makes a ton of sense! I do have a lot of coating since I did the EGR delete from the new manifolds. One thing that is still happening, I come to a stop, the car surges from 500-900 rpm's till I take off, every now and then it stutters. I cleaned out the throttle body and IAC valve and passages and it ran great for a week, then acted up again. I feel that this should't be happening because it shouldn't build up that quickly or even cause that much a problem. I'm testing to make sure i'm on all cylinders tomorrow because my fuel mileage is even worse now

davila0115

So i made an EGR block-off plate for the intake side of the EGR tube. installed that today. Going to see if that improves gas mileage. I just filed up....

However i got some questions....

I am not worried about spending money anymore on this dang thing i just want it running right... the wife says when its idleing she can smell strong fumes from the exhaust, she says it smells like gas... so idk. i have done everything except the injectors. and checked the new cts for correct working... i know the story behind the cts... but since my fuel pressure held for a long time. doesnt that mean the injectors are NOT leaking? so how would they run rich? or am i missing something.. i am still waiting for teh gaskets to come in and then i am ordering a reman set from Southbay.. unless you guys are certain that its not them... please let me know what you guys think... thanks a bunch!

ex-x-fire

If the pressure held that means the injectors arent leaky (leaky=bad spray pattern).
Check the vacuum to the map sensor, at idle it should be 16'' or more.
Check to make sure the timing is set right & that it advances when you rev it. You can even advance a couple degrees.

davila0115

Ok so then its good to assume that the injectors do not need to be replaced...

I will buy a decent vacuum gauge today or tomo and check that. Should i measure vacuum through the map line. or just at the back of the manifold? And is this at operating temp so idle should be around 650-750 rpm?

I checked the timing not to long ago and set it to 11-12 btdc. it advances with the ecm wire plugged in no problem. i checked it again a few weeks after that and was still dead on the money. so i think the timing chain is good...

I datalogged the ecm last night for about a 25 min drive. I logged a few times back in november before i started all this work on the engine and stuff. So i have a comparison. In last night log when i play it back i find that about 3 times the ecm throws in some knock retard for the timing. i never used to have that before. 9back in november) also.. sometime the MAP sensor skyrockets and the BLM goes up to about 139 instantly around the same time. My understanding is when there is LOW vacumm the voltage on the MAP is high and the reading is high. Meaning the throttle is open alot, or there is heavy engine load. When this happens in the log. the throttle is around 20-25% im not even stomping on it or anything... but then 3-4 secs later it just goes away and normal values seem to be present. I am trying to think of something that would open and cause low vacuum. but i dont know what. Any Ideas?

Maverick H1L

iTrader: (8)

First, injectors can have a bad spray pattern without leaking. The ports on the output disc can be plugged, or partially plugged, and the spray pattern won't be the fine cone it's supposed to be. Which means that an injector can possibly not be spraying enough fuel.

Second, check the vacuum both at the MAP and the manifold. Should be the same, to make sure the MAP supply isn't clogged.

Keep in mind that the knock counts pick up when the engine starts running LEAN, which causes knock and/or detonation, which is what the ESC system is designed to prevent. The ESC retards the timing when it sees the knock counts, because advanced timing causes detonation when the fuel mixture is too lean for other operating conditions. The opening of the EGR causes a lean condition momentarily. And the ECM kicks the BLM's up, adding fuel, to correct the lean condition.

BLM counts INCREASE to ADD fuel, and DECREASE to subtract. Should be around 120 (I usually ran about 121-ish when I was getting 30 MPG). Yes, high MAP is LOW vacuum (WOT), and low MAP is HIGH vacuum (idle or closed throttle). The number you should be paying attention to is the INT value, which is the LONG TERM fuel map.

Pull a spark plug and disconnect the injector harness to keep the engine from firing off. Crank the engine over and note the color of the spark. Weak spark can cause the gas smell in the exhaust. Yes, I realize most of the ignition system is brand new, but that doesn't mean that the wiring between the ignition switch, coil, and module is good, which can cause a weak spark.

Also, when you datalogged, you DID make sure the ECM was going into closed loop? And note the CTS temp, especially first thing before the engine has started (compare it to the IAT, should be almost the same when cold).

davila0115

Ok i can understand that. But it seems like i am having a rich issue not a lean issue correct? If its not spraying enough fuel, wouldnt that make it lean? I am still waiting to get the gaskets in, and prolly do them anyway.. it just kinda sucks haha.

I have one of those spark testers, from adv auto. Where you can set the gap and the spark will ground out safely. Would that be similar to what you are looking for. What kinda color am i looking for? Bright Blue?

Yes when i datalogged the ECM has no problem getting into closed loop. Looks like around 350 deg on the cat, 175-180 deg on the cts. The CTS, and IAT are about 6 deg difference. CTS being lower.

If anyone wants to take a look at this tunerproRT datalog file be my guess haha. At this point i am kinda at a loss as to what it can be.. gunna do said tests above and see what i get... lol

Maverick H1L

iTrader: (8)

Ah, but you're forgetting how the system works...

Let's say 2 injectors have clogged holes in the spray disc. The spray pattern is weak and the cylinders run LEAN. The O2S sees this, and sends the appropriate signal to the ECM to kick more fuel into the entire set of cylinders. That means that the 2 cylinders may now be running at the proper 14.7:1 air/fuel ratio, but now the other 4 are running too RICH. 2 cylinders of every 3 have too much fuel, so the exhaust smells rich. Which is why you should check the INT value and not the BLMs... You need to look at the long term trim to see what the ECM is doing overall, not just in the short term. If the INT is high, you know that the engine is being fed fuel overall.

Spark tester or a plug both do the same thing. Spark should be bright white, and not yellow or red.

davila0115

Nice ok.. well yeah that does make sense.

From what i have foud :

http://wiki.3400z24.com/ECM_tuning#BLM_.26_INT

The INT is the short term and the BLM is the long term... I know its wiki. but seems well written.. lol

davila0115

So i tested the Vacuum and it was at 18" at idle, car fully warmed up idle at 700rpm. Need to get the car emission tested soon. Wondering if this EGR plate is going to hurt the exhaust #'s they are reading? They wont care at all if this blocked, wont look, dont care at all. So should i leave it blocked or take it off to help emission? I am going to fill up today and check mpg. and check air pressure before i take it for a test.. lol

Maverick H1L

iTrader: (8)

If your car is using that much gas, you're probably going to fail the emissions test due to the HC being off the charts. Having the EGR blocked isn't going to help your NOx reading either.

However, do go for the test. That will tell you with a certainty whether or not the engine is running optimally. If the car passes the exhaust sniffer, you probably have a leak you don't know about (yes, I know you've said you're positive you don't have a leak due to the fact you park the car in an enclosed space, but that doesn't mean there isn't a leak on the return side of the system or something).

davila0115

So i got the car tested. I pulled the EGR block-off plate off the engine bc i started getting the SES light poppin on from it being blocked.. and if that would have popped on during the emission test they would have failed it whether or not the exhaust was good or not... BUT i did pass just fine... numbers we really low. so idk whats up with the car... I am going to assume i have a fuel leak now somewhere... All the main metal lines from the fuel filter forward to the soft flex lines to the motor are new, return line also. the only ones that are old are the lines that go directly to the tank.... I am going to assume that for my mpg to be so bad i would have to be losing fuel out of the car, and not just a bad regulator pushing fuel back into the tank.. correct? I will do some looking around and see whats up.. thanks for all the help...