Resolved Is this something to worry about - things I saw when I removed my upper intake?

vferrizz · Jul 29, 2023

I have worked through a bunch of hard start, rough idle checklists on the site and finally got my car starting and idling like it is supposed to. The one thing I have still been dealing with a hesitation when you push the gas pedal to the floor quickly and while driving the car starts to stumble at about 2500 RPMs. Fuel pressure at idle is good. Since my motor is bone stock with 32K original miles and now 31 years old, it seemed like a good idea to try can clean my injectors. When I pulled off the throttle body I saw what looked like a very small about water/antifreeze on the EGR spacer and a light coating of motor oil on lower intake runners 1,2,3,5 and 7 only. I sprayed some carb cleaner in the runners and it came off right away so I guess that means this may be a relatively new occurrence. Is any of what I saw an indication of a problem(s) I need to worry about and pursue?

Thanks in advance for the feedback.

Pinellas50 · Jul 29, 2023

That is all normal. Anti freeze runs through the egr spacer. The oil residue in the lower intake is a result of the pcv system working the way it should.

AeroCoupe · Jul 29, 2023

EGR spacer is usually connected to the cooling system on the car so coolant circulates in the plate and cools it from the hot gases of the EGR.

If you are seeing coolant in the intake that could have been from when you removed the spacer and some got in there or a gasket leak.

A very light coat of oil in the runners can be considered normal but I would check the mesh screen/filter below the PCV valve at the back of the lower intake and make sure the PCV valve is working. They are cheap so if original then replace them.

If there is a substantial amount of oil then those two items could be plugged and need replacing. This would cause all the crank case venting to happen through the hose connect to the oil fill neck and the throttle body which will cause oil to collect in the intake.

If the calve cover with the oil fill neck no longer has a baffle below it that is a direct path for oil to go into the intake.

The lower intake has a baffle below the PCV valve so if that is missing that is another problem.

vferrizz · Jul 29, 2023

Thank you both for the replies. I definitely need a new spacer gasket since it fell apart as I was removing it from the upper intake. I did check the PCV itself but not the mesh screen. I'll also take a peek at the baffle in the filler neck. Glad to hear this is not a huge turd.

limp · Jul 29, 2023

I would look at , squeeze, and poke every vacuum line and connection.... Your vacuum lines have to be needing some help at this age......Sometimes bending a hose exposes that crease or rotted area that " hides " normally....

vferrizz · Jul 30, 2023

limp said:
I would look at , squeeze, and poke every vacuum line and connection.... Your vacuum lines have to be needing some help at this age......Sometimes bending a hose exposes that crease or rotted area that " hides " normally....

Yeah I already found two broken / cracked vacuum lines. The line to the fuel pressure regulator was cracked and the line underneath the upper intake that goes to the smog stuff fell apart as I was trying to remove it. I am buying a bunch of vacuum hose now. I am hoping that is another symptom of how crappy the car is running.

tank76 · Aug 2, 2023

I had that same hesitation but in my case it ended up being the TPS

wbrockstar · Aug 2, 2023

vferrizz said:
Yeah I already found two broken / cracked vacuum lines. The line to the fuel pressure regulator was cracked and the line underneath the upper intake that goes to the smog stuff fell apart as I was trying to remove it. I am buying a bunch of vacuum hose now. I am hoping that is another symptom of how crappy the car is running.

Yeah any vacuum line that's cracked/torn/dry rotted allows unmetered air to enter the engine through the intake and this creates a lean fuel mixture once the ECU sees the lean reading from the O2 sensors.The ECU then richens the fuel mixture in an attempt to bring the air/fuel ratio back to a stoich (normal) value.So yeah it's definitely important to replace any/all hoses/lines that are leaking. The carbon canister to purge valve vacuum hose always dryrots at the canister and this hose is routed to the purge valve and a separate hose runs from the other port on the valve then up to the port on the front/underside of the upper intake.So be sure to check these because a larger hose like this one connected to the front underside of the intake can actually create a leak big enough to cause a stalling issue too.

Potomus Pete · Aug 2, 2023

Your going to be ok with those low miles. It might take a while to get it right, but you will get it. Just keep reading, and working on it. If you have problems in the future get a throttle position sensor

vferrizz · Aug 6, 2023

Potomus Pete said:
Your going to be ok with those low miles. It might take a while to get it right, but you will get it. Just keep reading, and working on it. If you have problems in the future get a throttle position sensor

I had previously replaced the TPS and the voltage output to the ECM was good but I never checked the reference voltage. Since a few of you mentioned to check the TPS, I checked the supply voltage this time and the output was about .3 VDC and the reference voltage was 1.5 VDC (should be +5 VDC). I put the old TPS back in and all voltages are in band. Car ran a little better but still stumbles under load. I think I found another issue but now I am going into the fuel pump direction so I should start a new thread. Thanks for the replies so far...I think I have it narrowed down, finally.

AeroCoupe · Aug 6, 2023

Just keep the same thread and update the title as you go. Provides background on the car as folks here help you work the rough the issues.

General karthief · Aug 6, 2023

I'd monitor fuel pressure, and vacuum.
Also check the sweep on the TPS, I had a cruise stumble, 1800-2200 rpms, the volt meter showed fluctuating volts in one spot.

vferrizz · Aug 13, 2023

Replaced the fuel pump anyway...its original, noisy and likely tired. Got excited when I vented my fuel system, barely heard the pump running and my fuel pressure was about 8 psi higher than with the old pump. I figured this would cure my original 2 year old troubleshooting saga that started with KOEO code 96. Road tested the car and even though it runs better than before, it still sputters under load at the 2500 - 3000 RPM range. If I put the pedal to the floor, car sputters badly. Cannot go over 60 mph in 4th gear right now. Tried 2 TPSs, voltage set at .85 vdc on each, and both about 4.8 VDC at WOT. Did a sweep test on both and did not see any dead spots. Ran the KOEO test, still getting codes 15 and 96 and still never get a code 11. 96 makes no sense, have good voltages through everything all the way to the pump. Ran a KOER test and I'm now getting all kinds of weird stuff: first test was code 66 and 65. Second test was codes 62 and 52. Tried a third test and got 51 and 52. Ran a cylinder balance test after the last KOER and got a 20. I have replaced all the spark plugs with correct copper Ford plugs, replaced all the wires, cleaned all the injectors and tested them with a noid light. Car is possessed. I think I need either an exorcism or a for sale sign. Need to have a few beers and think of which one I am going to do. No clue how to proceed, other than drink heavily for now. I appreciate all of you that have been posting suggestions to date...sorry for venting.

90sickfox · Aug 14, 2023

Have you tried sending the computer to ecuexchange ? Might be a good idea to pull the back off the computer and check for leaking caps and bad traces.

AeroCoupe · Aug 15, 2023

Code 15 is related to the keep alive memory or KAM. You should see if Pin #1 at the ECU harness has 12V+ with the key on or off. If not start tracing it back to find the break. Some chips will trigger a Code 15 as it may block the ECU from accessing the KAM so if you have a chip that could also be the cause.

Good read on Code 96 (very common on V8 swapped cars):

Code 96 Repair:

Got a code 96 on a 1990 Mustang GT. Replaced the fuel pump relay and got the pump from running on continuously. But, for some reason, I keep getting the Code 96 after wiping the memory. Checked wires on secondary circuit. In the process of replacing the EEC relay. All wires on relay read...

stangnet.com

Have you cleared the continuous memory codes?
1. Run KOEO Self-Test.
2. When the codes begin to show, deactivate Self-Test (remove STI ground). Codes will be erased without erasing KAM.

If that does not work then disconnect the battery for about 30 minutes and depress the brake pedal a couple times to remove any stored energy. Reconnect the battery and drive it to get it back up to operating temperature then pull KOEO and KOER codes.

vferrizz · Aug 15, 2023

90sickfox said:
Have you tried sending the computer to ecuexchange ? Might be a good idea to pull the back off the computer and check for leaking caps and bad traces.

Yes that is one of the first things I did over a year ago. They replaced the caps. I got a very generic letter with my ECU stating they inspected it and replaced some worn components. I installed it in the car and none of the symptoms changed.

vferrizz · Aug 15, 2023

AeroCoupe said:
Code 15 is related to the keep alive memory or KAM. You should see if Pin #1 at the ECU harness has 12V+ with the key on or off. If not start tracing it back to find the break. Some chips will trigger a Code 15 as it may block the ECU from accessing the KAM so if you have a chip that could also be the cause.

Good read on Code 96 (very common on V8 swapped cars):

Code 96 Repair:

Got a code 96 on a 1990 Mustang GT. Replaced the fuel pump relay and got the pump from running on continuously. But, for some reason, I keep getting the Code 96 after wiping the memory. Checked wires on secondary circuit. In the process of replacing the EEC relay. All wires on relay read...

stangnet.com

Have you cleared the continuous memory codes?
1. Run KOEO Self-Test.
2. When the codes begin to show, deactivate Self-Test (remove STI ground). Codes will be erased without erasing KAM.

If that does not work then disconnect the battery for about 30 minutes and depress the brake pedal a couple times to remove any stored energy. Reconnect the battery and drive it to get it back up to operating temperature then pull KOEO and KOER codes.

Thanks I'll give those suggestions a try. Also, thanks for the code 96 post...interesting reading. I have left the battery disconnected over night and erased the codes using the code reader. I'll try without using the code reader. The only other wildcard is I am confident my ECU has been modified. The car is originally an AUTOMATIC and there is a non-factory looking chip inside my ECU where the factory chip is supposed to be. The car seemed to run fine for about a year but who the heck knows at this point. Would love to find someone close to me that has a A9L I could throw in just to see if anything changes.

91 Black Hole · Aug 15, 2023

Hi. I have a 91 lx 5.0 and had the same problem. I fixed vacuum leaks, replaced purge valve, replaced coil, tune up, checked timing, ran codes and fixed items referred to by codes. My car ran great except under wot. Got to about 3500 rpm and would break up real bad. If I eased off on throttle would run better. I bought and built car for hpde and having this problem not acceptable. Turns out problem was TFI (thick film ignitor) unit on side of distributor. I got MSD replacement unit from American Muscle because it comes with the insulating film required. I usually prefer motorcraft but they have bad reviews. Put this on and car runs great and problem is gone. You need to turn distributor to get access to the screws but very easy to fix. Need special tool so order that when order tfi. Will also need to reset timing since you moved dist. Not as rewarding as drinking heavily but car might run better. It was very frustrating for me because every time I would fix something car ran great until next road trip and problem was still there. After replacing tfi I have done 6 different events and problem is gone! Hope it works for you.

AeroCoupe · Aug 15, 2023

Okay so wait a minute, you haven’t mentioned a chip until just now. Take a picture of it and and post that. It could be as simple as removing it and cleaning the contacts on the ECU board.

Do not do anything else until you do this. One of us will probably recognize the type/brand of chip and can guide you further.

What mods have been done to the motor? Heads, cam, intakes, MAF, injectors, stroker, etc.

vferrizz · Aug 19, 2023

AeroCoupe said:
Okay so wait a minute, you haven’t mentioned a chip until just now. Take a picture of it and and post that. It could be as simple as removing it and cleaning the contacts on the ECU board.

Do not do anything else until you do this. One of us will probably recognize the type/brand of chip and can guide you further.

What mods have been done to the motor? Heads, cam, intakes, MAF, injectors, stroker, etc.

Checked the voltage supply to the ECU pin1. Got good battery voltage of 12.86 vdc. The motor is 100% stock. Here is a pix of the non-stock chip (#4332 written on it):

Resolved Is this something to worry about - things I saw when I removed my upper intake?

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