Here is one for the group interesting problem

fc227

1986 Grand National
Joined
May 28, 2001
HI everyone,

I hope this post finds everyone well.

I am having a interesting problem. The car has been sitting for a while but started every week. Also we had heavy rain yesterday. Don't know if things got wet. but anyhow.

I am running several chips on a thumb wheel . Bob Baileys commander and Erics TT . 42.5 injectors , te44 turbo , stretch inter-cooler , ported heads , etc.

Anyhow no mater which chip I run same issues.

I fire it up , runs , I smell fuel . No leaks I can see. Hit the gas , it pops like its lean . popped when against the brake again like its lean The BLm did climb to 140, but
here is the kicker , I checked the fuel pressure ,its high but going off the sensor on the power logger don't know how accurate it is (55#) , So I disconnected the vacuum line and cranked the fuel pressure to 45 # (actually did this engine off , bypass jumper connect to run pump) .

Start back up not popping now , but the BLM climbed to 140 again ( I did reset the ECU). Sound like it has a miss , but it is smooth in gear.

Oh no codes !

I changed the maf , but the replace is bad (threw a code) , but the original back in. same thing .

Waiting until later to pull a plug and see what the plus looks like.

Any ideas ?

God Speed, and thank you in advance.
 
correction, INT is also going up to 140 , O2 is reading low ~ 300mv (Th e O2 could be the problem) but it is do this in open loop so.....
I did not pull a plug but the exhaust is black (Not blowing black smoke, but the pipe has a black sooty deposit).

Has far as I can tell I do not have a stuck injector the fuel rail appears to be holding pressure.

I can not see any air leaks, IAC stay around 20 up to ~45 in gear. egt is around 600 degree f.

something going on the ecu thinks the engine is lean but it looks like it running rich.
Oh it is also surging hole the throttle at on position and the rpm surges up and down.
 
It's not a good idea to let a car sit and just start it once a week without taking it for a drive. Starting it continually without it fully warming up just builds up moisture in the engine causing all kinds of issues. Take the car out for a drive.... warm it up fully and let the computer re-learn. You may have even fouled some of the spark plugs.
 
I agree , But i let it run for 1/2 hour . Always let it get up to temp.
 
I agree , But i let it run for 1/2 hour . Always let it get up to temp.
That's not good enough. The oil never reaches temperatures high enough to evaporate the water. Water builds up in the cylinders and exhaust. You have to take it out and drive it to fully warm it up. If you don't your better off just letting it sit until you can drive it. Disconnect the battery if it's going to sit for an extended period of time.
 
HI everyone,

I hope this post finds everyone well.

I am having a interesting problem. The car has been sitting for a while but started every week. Also we had heavy rain yesterday. Don't know if things got wet. but anyhow.

I am running several chips on a thumb wheel . Bob Baileys commander and Erics TT . 42.5 injectors , te44 turbo , stretch inter-cooler , ported heads , etc.

Anyhow no mater which chip I run same issues.

I fire it up , runs , I smell fuel . No leaks I can see. Hit the gas , it pops like its lean . popped when against the brake again like its lean The BLm did climb to 140, but
here is the kicker , I checked the fuel pressure ,its high but going off the sensor on the power logger don't know how accurate it is (55#) , So I disconnected the vacuum line and cranked the fuel pressure to 45 # (actually did this engine off , bypass jumper connect to run pump) .

Start back up not popping now , but the BLM climbed to 140 again ( I did reset the ECU). Sound like it has a miss , but it is smooth in gear.

Oh no codes !

I changed the maf , but the replace is bad (threw a code) , but the original back in. same thing .

Waiting until later to pull a plug and see what the plus looks like.

Any ideas ?

God Speed, and thank you in advance.

Symptoms are consistent with a failed MAF. Are you using OE style? Get a translator and a modern sensor, even if you have to borrow one for troubleshooting. If the MAF is connected, the computer typically won't throw a code, even if it's returning bad data. The condition to light up the CEL is a simple circuit check, not a data validation.

With a bad MAF connected, you get all kinds of odd fueling. If you disconnect the MAF, the computer falls back to a limp home table. I can't remember if that table is in the chip of if it falls all the way back to the CALPACK.

Replacement OE style MAF sensors from the parts store are not trustworthy. You can still get a quality 3" or 3.5" newer style from a dealer and the translators are available from several vendors.
 
some great advice right there...those plugs are probably shot from never letting her stretch her legs ..just running at idle...with rich conditions at times...
 
Along with the plugs that O2 never gets "blown out". Take it for a drive. The side benefit is the ice cream or where ever you go with it.
FB_20170226_12_03_54_Saved_Picture.jpg
 
I changed the maf , but the replace is bad (threw a code) , but the original back in. same thing .
Little confused, you replaced a stock maf with another stock or aftermarket stock maf? With the first one back in did it just run like you mention or throw a code like the second maf? I'm leaning toward the maf too.
AF = Mass Air Sensor Flow (MAF)
As stated at the beginning of this section, our cars come from the factory with a mass air form of fuel injection control which uses a flow meter, that we refer to as a mass air sensor, to measure the mass of the air flowing into the engine. Note that it measures mass and not volume. Hot air is less dense than cold air and thereby has less air molecules in a given volume than does the cold. Given that it is the number of air molecules in the cylinder that must be matched with fuel, it is important to know the mass.
The original factory mass air sensor is/was capable of measuring mass air flow from 3 to 150 grams per second. This is displayed on the scan tool over a range of some 3 to 255. 255 is numerical limit of the 8 bit processor in the ECM. The later LT-1/LS-1 mafs that can be used with Bob Bailey's Translator system can potentially flow a higher mass of air than the original units if the engine can use it.
This parameter is a big help in troubleshooting. One of the first suspects when the car is not idling/running correctly is often the MAF. This is particularly true if the original style MAF is being used. To verify operation, turn the key on, but do not start the engine. The AF on the scan tool will normally read 3. Then, start the engine. With a normal idle speed, it will normally read 4-6, and, may read 7 if the programmed idle is around 800/850 rpm as the faster idle will require more air thru the sensor. If the MAF is reading in this range, one can be pretty sure that it is not the problem that is causing the car to not run properly...particularly at idle.
Now, the MAF can also lose calibration at higher mass flows. As stated prior, 255 is the maximum number that can be displayed. Cars running boosts close to 15 psi or so may report less than 255..say 245, or thereabouts. As the boost gets closer to ~17 psi, the car will normally begin to max the reading out and one would expect to see 255, or very close. Design of the intake tract, engine size/combination, etc. will affect the actual number.
If one has been seeing 255 and then it starts reading 235, one may start having problems as one transitions to wide open throttle as the ECM believes the car is consuming less air and therefore provides less fuel.
If one has a logging scan tool such as PowerLogger, then the graph of the MAF output should be smooth with no spikes, or, sudden dips on a wide open throttle run.
The later style MAF/Translator systems are generally far more robust and don't cause many problems as long as the wiring is solid on the install.

How does under the hood look, any puddles of water? How about near the ecm? Any leaking in that area?
 
If you can keep it running long enuf to get up to temperature, post your SM numbers. You do have a SM, correct? For shits and giggles, remove the ECM and check for corrosion.
 
Can also be a misfire or dirty injector. Pull plug #6. Why? Because it often appears to be the last and most difficult one to get to, to be the problem. Lol
 
Thank you everyone,

took it out ran like poo . got it back home. started pulling plug wires ( I am not a fan of this , it could cause the secondary to internal short . ).

Turns out 3&6 where not firing , that coil pack on 3&6 was hot . Turns out the Ignition module went sour . I had a replacement. Runs great now , just have to calibrate my external pressure switch I use for fuel pressure.

Also need to have it aligned , it pulling to the right , I replaced the passenger side upper control control arm becasue the down pipe melted the bushing.

Then i will start driving it more regular since the weather is getting nicer (sorta)
 
A good rule of thumb is to replace both the module and coil pack together as a pair. Many will tell you otherwise and have gotten away without doing so and I don't doubt them. However, I chased the same issue a few years ago (popping, strong smell of fuel, high BLM's, rough idle, etc.). After troubleshooting and finding the issue, or so I thought, I replaced just the module with a NOS Delco and the problem went away. A few weeks later the car started to miss under boost but did not have the other previously mentioned problems. Replaced it with another Delco and it ran fine for a few more weeks before it crapped out again. Then I put a new coil and module on and it ran great for a long time until a rod knock developed, but that's another story... Coincidence? Just bad modules? Maybe.

Personally, you may just want to leave it as is but if the same problem reappears in short order, then change out the coil pack and module together at that time. You probably already know this but in case you do not - don't rely on a ohm's test to determine if a coil pack is still good (there are lots of threads on this subject). A DVOM will only tell you if the coil pack is shorted out, it is not a reliable indicator that the coil is still good. A bad coil pack may still ohm out ok but still be bad.

Glad you found your problem.
 
I'm going to call Jack Cotton next week if he is open and order a replacement coil and module and another maf (The back up I had is bad).

I also had to kick some mice out from under the back seat. that's another mess I have to take care off . My own fault for not driving it more.
 
Glad you found it the issue without throwing parts at it. If you are still running the stock maf, it would be wise to look at a translator and new style maf. They really are a better choice.
 
Agreed. One more issue I found . Racetronics fuel pump hot wire kit , the connector failed . Anyone know what the proper name for the style connector is ?
 

Attachments

  • fpwh-076-l.jpg
    fpwh-076-l.jpg
    80 KB · Views: 180
They have a couple of different ones. The ones that connect to the stock connector are weatherpack. I have a different one that goes with a different pump connector and I think its a metripack but i'm not sure.
 
It's a spring loaded ground clip. (Not the exact name though)
 
Top