Hey all, my 1989 e150 with the 302 has almost always had an issue with the idle surging and dropping when starting the engine for the first time of the day. I learned to just live with it as it only happens for 15 or so seconds when I first start the van. Sometimes the engine dies and I have to start it again but lately its been wanting to die a lot more often so I've learned to just baby it with a little gas when the idle drops too low and after 15 or so seconds it's able to keep itself alive without the gas and I go on with my day. Well today I decided to do a few things to the van and I also wanted to see if it would start and stay running on its own without me babying it with the gas and it wouldn't. I tried Over and over but it would just die right after I started it. This is a bit disconcerting. I hooked up my fuel gauge to the rail and fuel pressure looks good (high 30's). I have a lot of random spare parts from other ford vans for trouble shooting so one at a time I swapped the IAC valve/solenoid, MAP sensor, ECU and nothing really made a difference. I checked the cap and rotor, checked my vacuum canisters to make sure they hold vacuum, looked at all the vacuum lines trying to find anything out of the ordinary that might be leaking but Ive yet to find anything. In the past I've cleaned the injectors, replaced the intake manifold gasket, throttle body gasket, throttle position sensor, coolant temp sensor, air charge temp sensor, among many other things. I have yet to adjust or check the timing on this van, is that something I should look into given the symptoms? I have a timing light but haven't taken the time to look into how to adjust the timing on this van. I'm convinced its something vacuum related, maybe EVAP related? I need to learn more about the TAB and TAD solenoids, diverter valve, smog pump etc.. I read the TAD solenoid is active before the engine warms up, I'm wondering if a bad TAD valve could cause the symptoms I have and if 15 or seconds of the engine running is all it would take for the TAD to turn off in normal operation? There is no vacuum coming from the TAD solenoid to the air diverter valve while the engine is running, Is that normal? Any help would be greatly appreciated as I've basically fixed every issue with the van since I purchased it except this one annoying one!

 

ECM maybe? Some of these EEC IV's have capacitors that will eventually leak causing numerous issues.

 

I was thinking that was a possibility so I went ahead and put a matching ECM from a junkyard van in to see if anything changed and I had the same symptoms. Of course there is a slight chance the junkyard ECM suffers the same problem the original causing the same exact issue but I'm leaning towards it being something else. I recorded a video of it trying to start up and listened to it over and over. It sounds to me like the first thing that changes before the engine dies is the sound of the air getting sucked through the IAC Valve stops flowing. Then everything else follows. The IAC Valve is clean as a whistle, so are the ports into the throttle body. I bench tested the IAC solenoid with my multimeter it checks out. Seems like the ECM is telling the IAC to shut a second after ignition. Not sure why it would do that. If I can post videos on here I'm happy to upload it. Maybe I need to put it on youtube first?

 

Posting your video to YouTube would be best as it can be linked to from here and it might gather other POV's from unexpected other viewers too.

 

Well I just noticed something interesting. I was hunting around the van looking for a potential vacuum leak and took one of the ford coffee can vacuum reservoirs off the frame of my van and discovered three large cracks. I followed the vacuum lane from this van and it goes to some kind of “T” valve and from there one short line goes to the vacuum tree on the intake manifold plenum and the other longer line goes to the cruise control mechanism. Seems like I found a pretty obvious vacuum leak! I’m actually on the road at the moment so I cleaned off the cracks and JB welded them. Very curious to see if it makes a difference when I start up the engine in the morning. I haven’t seen any vacuum diagrams that show this second coffee can reservoir on the frame of a van or truck. I only see the one that’s near the passenger side wheel well under the hood. I checked that one on my van as well and holds vacuum. Is it possible the cracked can on my van is the source of my issue? Thanks!

 

Waiting on your update... Also check your power brake booster. The simplest way is to just unhook the line and plug it off then start the van..There are some good videos about testing vacuum brake boosters though. Mine is just now starting to leak a little as I can hear it when i press the brake peddle but it is not bad enough to cause stalling issues yet...
The connector for my power steering pressure switch was just laying loose and one day i connected it. The next day i started having trouble with a very low idle and the engine stalling at stops. I disconnected the switch and reset the ECM and all is well now.

I was having issues with the up and down idle on cold starts as well as if the engine was up to temp and i parked to go into a store for 15 to 30 minutes, the engine would surge and sometimes want to die within the first 15 seconds of restarting the engine.

I solved the issue but cant tell you which part fixed it... I had been collecting sensors for almost 2 years and one day my son and I went out to the van and did a tune up and changed most of the sensors. After each sensor change i restarted the engine just to make sure the engine would run but did not let it get up to temp.

I changed plugs, cap, rotor, and wires. They were in good shape as they only had around 40k on them..
I changed the ECT, ACT, IAC, MAP, and the EGR solenoid vacuum valve.

Below is the EGR valve. When I searched for the TAB/TAD, they seem to be sold as a pair according to the parts sites I have looked at. But one of those sensors did fix my issue.. Right after I bought the van I had the throttle body off and changed the EGR valve, TPS, FPR, and MAP sensor at that time I still have the O2 sensor, TPS, and ECM on hand to change out. Yes TPS again as i have a slight surging with the throttle held at a very low speed.. And yes I changed out the MAP sensor a second time. First time was a NAPA brand and this last time was a Ford brand..
Most of these sensors can be tested with a meter... I was changing them out mainly because they were 33 years old and I was just doing a refresh to help prevent future breakdowns.

 

Sorry for the late reply. I've been out camping without service for a bit. Once I plugged those cracks on the rusty old coffee can the newly created vacuum pressure crumpled the coffee can and created new cracks haha! I decided to throw a thick plastic apple sauce jar on the line since I was in the middle of nowhere. The jar couldn't hold the pressure too well either but at least didn't crack. That didn't solve my issue unfortunately, must be something else and sure enough my check engine light came on and off on the trip (at times I was about 20 miles from the nearest paved road which was also about 25 more miles from any time of services!) I happened to have my code reader and the codes presented were 54 and 98. I've read that those two codes in combination mean the ACT sensor isn't connected to the ECM for some reason. I did replace the ACT with a new one a few weeks back so maybe its a dud or maybe there's an issue with the wiring. Now that I'm back home I'll be doing some more trouble shooting as well as picking up a better vacuum reservoir to hook up under the van.

 

Glad you made it back home okay!
You can test the ACT with an ohm meter. It will read certain ohms at certain temps. Do a search on ACT or ECT + ohms and look at pics. You will probably find a lot of scales showing the resistance at different temperatures. The ACT and ECT use the same scale. I would post one for you but don't have a pic saved.

Here is the one i bought for my van. there may be an updated part number but this is the one I bought.. Your old one may still be good.. That's my old one in the pic.


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I have a pin out chart of the PCM/ECM but not sure if the wire colors would be the same on your 89 It came from the emissions section of a manual I came across so may just be a generic diagram for the OBDl
It shows pin 25, circuit 310, Y/R wire being the ACT input.. Maybe your old sensor is bad or the connector is loose...

 

I cleaned up my old ACT and put it back in and reset the ECM to see if anything changed. Unfortunately it seemed to have the same symptoms (long crank before it starts and then the high then low idle then it stalled). Then I thought about how you tried unplugging your power steering pressure sensor so I went ahead and unplugged mine and started the engine. It fired right up! No long cranking and it sounded a lot different, the idle sounded good and strong for about 8 or so seconds and then it dropped and almost died but then picked back up and finally found a steady idle. I don't know what that means but I found it really interesting. Seems to have done something for the better. I'll experiment more soon. I still need to test the ACT sensor like you said and replace the vacuum reservoir.

 

Well I pulled out the ACT sensor today (the original ford one I had just put back in) and bench tested it with an ohm meter and it seems to have failed the test. I had no reading when connecting a probe to each prong of the sensor. I tried the one I pulled out the other day and got nothing as well. I touched my ohm meter's probes together to make sure the fuse was still good and it is in fact working properly. I'm a little surprised the original ford sensor and the new sensor are both returning the same results but it seems like thats what the test is telling me. I'll go ahead and order a new Standard Motor Products sensor today since I don't seem to see any Motorcraft brand sensors available and the Standard Motor Products one looks the most similar to the OEM one.

I also just tested the ACT wiring harness by connecting the ground probe on my multimeter to the negative battery terminal and trying the red probe on either of the two contacts on the harness and I didn't find a voltage reading on either. I believe I should be finding 5v on one of them. I wonder if this problem is a two parter.. I'd like to sort that out before putting in a new sensor so I'm not just frying sensors due to some kind of short. The wires from the plug disappear into a very thick loom of all sorts of wires. Any ideas where it leads to so I can check the other end for damage? Does it go straight to the ECM?

In other news I picked up a 46oz can of Dole pineapple juice today to replace my rusted out vacuum reservoir and its an exact match. Fit right into the coffee can bracket on my van. I just used some epoxy to put the fitting from the old coffee can on the juice can. Thought that might be useful info for others since you can get those 46oz cans of dole pineapple juice everywhere for about $3.

I'm still curious if anyone else has a second coffee can vacuum reservoir attached to the rail of their van like mine? Seems like people only talk about the one under the hood near the passenger side wheel well.

 

So now I just took my vacuum pump tester out to test vacuum on my TAB, TAD and EGR solenoids by plugging a hose from the pump to the bottom vacuum line on each solenoid one at a time. Both TAB and TAD solenoids seem to hold vacuum perfectly but the plastic EGR Solenoid/valve (the one you shared a photo of @annaleigh ) doesn't hold vacuum whatsoever on either of the top or bottom vacuum ports. Now I'm not sure if its supposed to or not so I figured I'd check in to see if anyone knows. Is there a better way than this to test the EGR solenoid?

 

I'll have to take a look for the second vacuum reservoir. My first task in the morning is finding out why one of my rear tires went flat.
The EGR solenoid does not hold vacuum... My old one didn't neither did the new one.. Seems I found a post on o mustang forum about how the EGR solenoid works. Ill have a quick glance and see if the link might still be highlighted

 

^^^ Check your valve stem unless there's an obvious cut or puncture. I've had a few develop a slow leak due a bad stem---that's just one reason I run the metal valve stem caps.

 

Oops! realized yesterday that the multimeter I used to test my sensors the other day doesn't default to auto-range for resistance so I retested the ACT sensors in the proper range and the OEM ford one is in fact good and the cheap new one I had in that was giving me the check engine light is in fact bad. Anyways the OEM one is back in, check engine light is no longer showing up but I still have the erratic idle symptoms so I tested for codes and got 41 which has been intermittently with the van since Ive owned it. I took off the o2 sensor to take a look (its got less than 10k miles on it) and it seems good, cleaned it off a bit, its a 3 wire sensor and the harness it plugs into is 3 wire as well. I believe that means its a heated sensor?

I also took off my EGR valve and inspected it, looks pretty clean in there and the diaphragm holds vacuum as it should. Took off the throttle body and gave it a good cleaning, especially that tiiiiny hole that you found some crud in on yours @annaleigh . I decided to start the engine to see if cleaning out all the little passage ways of the throttle body helped at all and it did seem to make a difference. With it running I sprayed a little carb cleaner through the IAC passage way in the throttle body and the engine perked up a bit like I was giving it gas. Would that suggest my van is in fact running a bit lean like the code 41 indicates? I'm considering running some seafoam through the throttle body and seeing what that does.

Checked my air diverter valve or "thermactor" to see if it switches air flow when vacuum is applied and it seems to work. The few times I've unplugged the vacuum line to the thermactor while the van is running it hasn't had any vacuum going to the thermactor. I need to look up when its supposed to be activated so I can check if it ever does. I went hunting for my Canister Purge Regulator valve today because I found a post on here from someone with similar symptoms as mine who discovered their Canister Purge Regulator Valve was faulty and he replaced it which solved his issue. I couldn't find it so I checked the vacuum diagram sticker on my van and it doesn't look like there is one! Oh well!

I'd like to hook up a little fog machine to my tail pipe and check for exhaust leaks upstream of the o2 sensor as I've read that can cause a 41 code. Also I'd try running the fog machine through the vacuum system to see if any leaks shows up there as well. Been meaning to try that out some day and since its almost halloween its time to bust out the fog machine!

One last thing I've been meaning to do is check the timing. I believe I've read if the timing is off I could have similar symptoms as I'm having. Timing is something I've never messed with but I do have an old timing light on hand for such an occasion.

 

Also in case this is helpful here's a short clip of what its like starting the engine cold. I threw on a fuel gauge and vacuum gauge in case it showed anything interesting. It used to only sometimes die when the idle went real low but now it basically dies every time the idle drops low on a cold start. I have to baby it with some throttle for 15 or so seconds to get it past this stage and running. In the video I'm not touching the gas pedal, I'm just letting it do its thing and stall.

Video link:
https://imgur.com/fuGcJc2