TFI & Hall Effect Sensor Question..

My '86 Ranger has a rebuilt 2.9 engine in it with new heads and all. But I have been having consistent issues with it running rough even before I had the engine rebuilt. However, the 'stuttering' issue seems to have finally fallen into a pattern which is when the engine finally gets hot, the engine will start to miss more and more until it simply won't start anymore. Once I let it cool down, it starts up fine and runs smooth. When it starts to heat up, it behaves sorta oddly, almost like the more I push the gas pedal, the more it misses... like it won't advance timing or something.

anyway, I replaced the TFI today and there is no difference, same behavior... Is the hall effect sensor prone to heat failures too?

I am suspecting that when the engine was rebuilt that the distributor was installed with the rotor pointing in non-stock position. My distributor number 1 is a half rotation off (in 5 o'clock position at #1 TDC). I have the wires all shifted 3 spots so it seems to be fine, but I figured that perhaps the hall effect trigger disc might not like this configuration... not sure if the gaps in it are okay with the distributor rotated like this and if it might be confusing the ECU. Is this okay?

thanks in advance... Im gonna verify my TDC tomorrow and put the rotor in the 11 o'clock position (which is where my Haynes manuals shows) and see if it helps. Not sure if I should try putting in a new Hall Effect or if Im looking at the wrong stuff.

JA

Sidenote: look in to a tfi relocation kit that moves it away from the heat source and mounts it on a heat sink

Okay, a little followup on this one...

Pulled codes... have an 11, 11 then 18, 18. Sounds like the engine is thinking the same thing I was... however this morning I replaced the following...

CPS (Hall Effect Sensor, this sorta sucked)
MAP
IAC

Yesterday I replaced the TFI.

I went through the TFI worksheet... all was okay up until #8... TFI to distributor ground... but I might be confused... with the TFI connector *disconnected* I have 666 ohms from pin 6 (black) on the harness side to ground. I have 0.7 ohms from pin 6 (distributor side) to ground. When I connect... then obviously I have 0.7 ohms from pin 6 to ground (block).

On #9... check the hall effect out at SPOUT... I get a solid 5.1V while cranking.

Am I looking at an ECU next I suppose?

Again, the engine works great at cold... then gradually dies the hotter it gets. Here is an example... start up in the morning at 70 degrees outside... as long as I keep velocity and keep the air moving under the hood, then I will be okay with slight spurts of misses... if I stop at a red light, that is when trouble starts... engine compartment gets hot and I start to buck and chug... when I push the gas pedal, it seems to actually decelerate... if I pump the gas, I can sort of keep it going enough to make it out of the intersection, and as I get moving again and up in higher gears it smooths... however, Im pressing my luck at this point because if I have to stop again and the engine compartment gets too hot, the engine just sputters and dies. Not to be restarted until the hood is up for 20 minutes and the compartment cools.

On a novel note, I tried getting the engine hot in my driveway and spraying various things down with freeze spray to see if it would suddenly become healthy, but nothing so far. Im out of freeze spray now. :-(

sincerely...

Dead Ford in Colorado

looks like EGR is the issue...

Okay, so I have an update on this... I put in a new hall effect sensor and got it timed correctly, now it doesnt' die but it still runs quite poorly. I pulled codes and got a 34 and an 18... the 34 is the EGR valve, which made me think of something...

When the engine was rebuilt, the guy put on headers and removed the line up to the EGR valve. I looked and sure enough, the bottom of the EGR is just open to the atmosphere. After reading these forums, it sounds like I should either put an 88+ ECU in there or put the EGR line back in... Im not a welder or exhaust guy, but I think I will have to have my driverside header taken out and put in one with a tap OR get the 88+ ECU right? Are those my only options at this point? Can someone verify?

thank you!

Hi Pete.. thanks for the info...

the 34 was the KOEO code. All codes were cleared after I replaced the TFI and Hall Effect Sensor (stator).

I actually just found a nice '88 ECU on Ebay for $75 so I will go to my scrap yard and see if I can find an '88 EGR block off plate for the intake. The ECU should be here on Saturday hopefully so I will report back. I live in Colorado so I expect that the truck won't pass emissions anymore in this condition, plus there is no CC... but luckily I have the truck registered in Wyoming.

So along those lines.... I am going to remove all the EGR stuff now... I have the '88 ECU showing up on Saturday, the local scrapyard has an EGR block plate from an '88 engine which I will pick up tomorrow. Upon taking off the EGR, it looks like I can also remove the green vac line to the EVR, then remove the EVR, and the remove the red vac line to the manifold where I can cap the manifold nipple. Now what about the little black box on the drivers side of the manifold that has a vac line into the EGR and has two wires into it. It is on a little spring bracket bolted down right at the throttle cover. I can't quite figure out what that is, but I suppose Im just going to leave the electrical connection on and take the black vac line off between it and the EGR. In the end (and looking at the 1988 2.9 vac chart), I will only really have a single vac line from the manifold to the MAP... super simple!!!

Once I get all of this done, I will see if I still have the 18 code. Im going to remote mount the TFI while Im doing all of this too. That will be step 2.

alrighty, things are going in the right direction, but I still have some of the same issues... but new codes...

First an update... I put in the 1988 MT 4x4 ECU, removed all of the EGR components and capped the unused nipple on the intake manifold vacuum header. The engine runs much better now, no more pinging and it just runs smoother. In the process of doing this, I also remote mounted the TFI module to the top of the firewall on an old Ford TFI heatsink. I can't imagine it was happy on my hot distributor.

So, now the bad news... when the engine compartment gets really hot, the engine will buck and snort on acceleration (bad hesitation for 1 second, accel for 1 sec, bad hesitation for one second, repeat). Once I get moving and get some air through the engine, it will stop. If I get stuck at a red light for more than 1 minute when it is 90 degrees outside, then the truck will just start missing badly and then stall. It will turnover but not run until the engine compartment cools down, usually about 20-30 minutes with the hood up). Even at this point, if I can keep the truck moving, I can keep in going even tho it continues to buck and snort on accel.

So, with all of this, I have new codes...

KOEO 95 - Secondary Fuel System
C 18 - Intermittent SPOUT
C 29 - Insuficient VSS or Programmable Speedo
C 95 - Secondary Fuel System Fail

I have a new Fuel Pump and Fuel Pressure Regulator on it already. The air side of the FPR is clean and dry. Also, I did go through the TFI worksheet and had good voltages at the TFI pins and SPOUT connector, but I have not checked them at the ECU yet. I got out my heatgun as Psychopete suggested and went through as many things under the hood as I could... TFI, IAC, IAT, TP, FPRelay, FPRegulator, Coil and really couldn't get anything to make the engine start missing. However, around the FPR, things got a little shotty and I looked at my Fuel Pressure, it was down around 25PSI and when I accelerated (the FP actually dropped, it is normally at 30PSI at idle) it did this a few times and then started increasing as I pressed the gas pedal. So, it seems that my FP is somehow dropping instead of increasing upon accel... isn't this opposite of normal? I tried taking the Vac line off and plugging it on the Intake Manifold and the engine sorta just ran poorly but the Fuel Pressure was steady at 40PSI. I don't have a vacuum gauge to see if the FPR is getting the wrong vac (positive) when I accelerate.

If anyone has any bright ideas, shout em out... Im going to keep plugging along now.

nother update....

Codes

K 95
C 18
C 41
C 95

I definitely see that the issue is on the fuel side now... my fuel pressure starts around 31psi and then as the engine runs for awhile... like 20 minutes, starts dropping down to like 10psi... I think that is where Im getting the code 41 stuff now. Interestingly, when the engine is warm, when I press the gas pedal, the pressure drops. As I let off on the pedal, the pressure comes back... so it must just be a weak supply.

As I was bleeding the pressure gauge, it seems that there is air in the rail too. I had this issue before (my truck has two tanks). My tank switching valve is toast so I actually took it apart and plugged the lines to the front tank with epoxy and set the valve in the position for the rear tank to flow through all the time. So, how can I have air in the rail? I don't have any gas leaks, the FPR is new, the Fuel pump is new.

Is this a tank pump issue? Would that give me air in the rail?

thanks... I think Im personally at a dead end on this so if anyone has any ideas throw them at me.

It sounds like a fuel flow issue maybe a plugged strainer in the pickup tube in the tank. Your probably sucking air at the switching valve for the two tanks. If your only gonna use the one tank hard pipe it without the valve or fix the valve properly. Allways fix the obvious first. Disconnect the fuel line out of the fuel pump and stick the hose in a large glass jar and check for volume and bubbles if the flow is slow the pump is bad or there is restriction in the suction line. You can run the fuel pump manually using the EEC test connector.

Im gonna take it down to my local mechanic that has a lift for this, I can do under the hood stuff easy but not so much under the truck...

Anyone know of a replacement for the tank switch valve? I sorta kick myself as my Ford dealer had an NOS one about 8 years ago and I didn't buy it (It was $200 tho)... but now there isn't anything out there to replace it. The ones that the auto parts stores have the wrong shape to work properly.

I found this post too... http://www.therangerstation.com/forums/showthread.php?t=132448

which also sounds like my issue. Im just gonna pull the middle tank out of this beast if I can't find the fuel line switch valve and run the hard line to the fuel pump as you suggested. I will report back...

Okay, I got this fixed, but since it was not related to this thread topic, I started a new thread...

http://www.therangerstation.com/forums/showthread.php?t=141663

The issue ended up being the in-tank pump. It took me 6 hours and about $125 in parts but things are cleaned up and running nice. The symptom that gave it away was that as the engine heated up and the truck was on 90 degree roads, I was losing fuel pressure and getting air in the rail.

Glad you found the problem and posted your fix.

Richard