I've got a 94 conversion van with a 302 & automatic. Cold starts are almost instantaneous as the key is turned. Lately though, starts with a hot engine will sometimes require 4-5 seconds. During that time it seems to be "on the verge" of catching when finally it does. Idle RPM floats up to around 1200 to compensate for the roughness that smooths out in 5 seconds. Idle RPM returns to normal. At that point all is well and no drivability issues. I've seen many posts about the ICM getting hot and causing a "no run" or stall condition but my problem is limited to the starting. I ran a code scanner and nothing to show either in recorded codes or any temporary ones. Do you think we're still looking at the ICM?

 

I did a few searches and didn't really come up with anything to pinpoint your problem.. I would think it it were the IMC , from what you and I have read, you would be having other problems too. I have read to check the fuel pressure because the FPR gets hot and can have a weaker pressure when hot but that seems like it would cause other problems too.. Unless it takes a little more pressure during start up.. ECTS (engine coolant temp sensor), if it is going out, it may not set a code at first but if the PCM thinks th engine is cold it could send more fuel basically flooding the engine.. It seems like it would run rich in this case.., Have you noticed any gas smell like running rich or loss of fuel mileage? Read TPS can cause this again causing it to flood out on start..
I also read in some of the posts where people have changed all these parts and still have the problem!

Perhaps thinking in the direction of what is causing the uneven idle on start up might give some clues. My 88 does the uneven idle at start up for about 5 seconds and then smooths right out, but not every time. It does it more so with the AC on... I actually had the engine to die a couple of weeks back when I started the van with the engine hot, AC on and put it in gear before the engine smoothed out. The difference in mine and yours here is that mine always starts right up, it just has the uneven idle for that 5 seconds or so. I do think mine is running a little rich though because I can smell it sometimes but not all the time... I replaced my TPS, EGR, O2, and FPR in the last 2 years though.. I have a ECTS that has been laying around for a couple of years and will be changing it in the next few weeks. I will let you know if that makes any difference if you don't find the problem first.

I have also thought about the PCM,, those capacitors that go bad.. I have read wehre folks have changed the PCM while hunting down minor issues and they report that their van Runs much better..
I don't have the speck but you know you can ohm out ECTS and tps to check them

 

You may be on to something with the coolant temperature sensor. I DO smell fuel after it finally starts but the exhaust smells neutral once it's idling. Once I can corner a helper (I'm in a wheelchair) I can meter the TPS and coolant sensor. My O2 and fuel pump are less than 6K miles old Thanks for responding. Wish this bird was OBDII.

 

Might also be a minor case of vapor lock.

 

This is a Ford van, not a Chevy Corvair. Sorry, I couldn't resist. Maybe I need to whip me up a "cool-can" from the old street racing days.


Is it coming or going?

 

Yea, well it can happen to it too. I had it happen climbing up out of Boulder Canyon Nevada in a 95 E150. Clutch fan quit working and it got hot enough in the box to cause it to vapor lock. I hadn't a clue as to why it quit running and was sitting on the side of the road in 120* heat when a Park Ranger drove up and asked me what was wrong. When I told him it just quit, he told me it was vapor locked. I told him this was fuel injection. He told me that place was like the Devils Triangle and vapor lock happened all the time. I pulled the engine cowling and let it cool off for 30-45 minutes then it started up. You get the right conditions and it CAN happen. Engine box too hot and fuel that's a low RVP rating that vaporizes at a lower temperature and that'll cause it to vapor lock.

 

Well was wondering if you have had any time to diagnose your van any more and if so, what did you find?

I just replaced the ECTS today and haven't really driven the van enough to say what the difference is. I can say that the engine idles much lower now then it was. Almost to the point where one would think it might die, but it doesn't. It is probably just that I am used to the idle being just a little higher. That does seem to indicate that perhaps the old one was in fact bad. My guess is that it was running in open loop.. I will check my fuel mileage for this next tank and see what it is..

A tip here:
It requires a 1" deep socket. Not all 1" deep sockets will fit either because the connector on the sensor has to fit inside the socket. I seem to have misplaced a whole tool box full of deep impact sockets but I found one that was just a little larger then 1" It is a little tight in there and with the socket not fitting correctly, I snapped the connector off of the threaded part of the unit. Of course though that made it much easier to remove as I do have a 1" socket that fit right on with the connector out of the way.
I did not drain any antifreeze out of the system and so when I removed the sensor, I lost about a 1/2 cup of coolant which disappeared off the top of the engine somewhere because by the time I was finished, all was dry.
Well having broken the old sensor, there is no way to test it. Knowing how to break one, I had to be careful installing the new one. To work around this I used a 1" offset box end wrench. My AC suction line was in the way so I could only turn the wrench one notch at a time and had to work the wrench on the sensor just right to do that.
Hopefully your AC suction line might be configured a little different then mine.
Well that is about it except for perhaps using some sort of thread sealant. I have read not to use teflon tape because it can keep the threads from grounding good. I believe what I used on mine was a heat sink type grease of some kind. When the old sensor broke there was a thick grey like putty down inside the old sensor that got all over my fingers. With the old one removed and coolant coming out the port, I just wiped the putty onto the threads of the new sensor.. Got it back together and no leaks.

 

Try Teflon pipe thread sealant. Just the plain old stuff you buy at the hardware store in a can. Or Antisieze if you want a good ground.

 

Might be a bad MAP sensor causing the hot start issues too.

 

OK friends, I received my ICM from RA (selected the Airtex-Wells) and replaced it. Battery had to be removed for access and I think the computer lost my engines tune settings as the first start and idle was pretty rough. A 25 mile trip of mixed hiway and city came next with a few stops for shutdown, wait and restart. All was good. Let me forewarn anyone who is replacing the ICM to do it where you have a drill press to use. The module has a deep recess for the fasteners Ford used to attach the module to the heatsink. I think it would require a 5mm thin wall, deep socket to reach it. I didn't have anything that small (Harbor Freight has a 1/4" drive set 5mm-14mm for $10) I tried grinding the outside of a 1/4" nut driver down and while it could then reach the fastener, it turned without gripping it. So, I drilled the head off the fastener and replaced the mounting hardware with 4mm Phillips head screws. The heatsink was already machined for the metric threads. Seems nothing is as easy as it should be.
Almost forgot, I replaced the MAP a few months ago due to a code indicating it was bad. $$ AC-Delco part, should be OK as no codes thrown. I really should verify the 5v supply and sensor output however. I'd like to pull the PCM and replace the electrolytic capacitors in it. Does any one know the values? I'd prefer to have them on hand so I could replace and install in one step. Panasonic has a line of high temperature rated caps that I would use.

 

below are the capacitor values and part numbers. I had just ordered these for my 95 5.8 and E4OD but on closer inspection of the PCM board, found a lifted solder pad under the tantalum cap. I decided to go with a rebuilt in lieu of repairing. As far as hot start, i had previously read that your IAT (Intake Air Temperature) sensors can get gummed up with age and not respond as quickly. Cheap part to replace and easy to get to.DetailsAvailable QuantityBackorder QuantityUnit
PriceExtended
Price
EEU-EB1J100S
P13467-ND
CAP ALUM 10UF 20% 63V RADIALAvailable
QuantityBackorder
QuantityUnit
PriceExtended
Price1000.19300$1.93
EEU-FR1E470
P14411-ND
CAP ALUM 47UF 20% 25V RADIALAvailable
QuantityBackorder
QuantityUnit
PriceExtended
Price1000.21500$2.15

 

Thanks MotoJoe, do you recall the quantity needed for each value? Good ol' Digi-key, been using them since the mid 70's when their catalog was maybe 20 pages. BTW, I replaced the IAT when I did the MAF sensor. Both parts threw codes. My problem hasn't left yet and I now know that it can happen for either cold or hot starts. I'm leaning toward a fuel filter next.

 

There is 2 of one, and 1 of another. I bought 10 of each just to have a few extra on hand.

On the long hot start.
I had the same issue and prior to replacing PCM. I decided to replace the fuel pump due to age of the vehicle and due to erratic engine misfires when very hot and humid outside. I thought that the fuel pump was potentially loosing pumping pressure when the temperature of the fuel in the tank was high, causing vapor lock and misfires. The PCM is what ultimately corrected the issue.
During the fuel pump replacement, i replaced the fuel filter. The filter was so old, that it was shaking around like marbles is a jar. All of the debris and filter element from 1995 to present, went upstream to my injectors and fuel pressure regulator. So the next items i replaced were all 8 injectors as well as the fuel pressure regulator. This took care of my long hot start. I know this was a lot of parts to throw at this van.
My assumption is that 1 or more of my injectors was leaking after shutting the engine off. If shut off for only a short time (less than 30 minutes) a, or a few cylinders would flood and cause long cranking to clear the flooded condition. This was confirmed by smell of exhaust.
Replacing all 8 injectors is something i would not have done if the original filter was intact when removed.

Perhaps before replacing injectors, try several strong fuel injector cleanings.

 

I think I'm seeing the result of an injector that continues to dribble when the engine is turned off. The 5-7 second long starter effort had me thinking weak fuel pump, however it was replaced by the previous owner just before I bought the van. When it does start I can smell a "chemical odor" in the exhaust which may be a really rich mixture burning off. Working on that theory I replaced the fuel filter and added a can of Seafoam along with a can of Gumout's Tune Up. This past Sunday I drove for few hours with a mix of road conditions and covered 120 miles. I could tell at the end of the drive that throttle conditions such as "tip in" and part throttle in lower gears were more tractable and responsive. I'm guessing a piece of trash was hung in an injector and the added solvents worked it through. My odo shows 123K.(It was parked for 8 years) What's considered a full life for an injector? Thanks for all of your input!

 

My van sat for years too. The PO got it running just before I bought it. They had to replace the gas tank, tank pump, and filter. I was thinking that I may have a dripping injector because of the way mine starts up sometimes after the engine is warm. Changing the ECTS seems to have helped uneven idle after a hot start up greatly. My fuel mileage was averaging around 10 mpg in city driving with many little short trips. I checked today when I filled up and I am now getting 13.5. Of course it is hard to be really accurate on just one fill up as I probably did have a little bit more highway driving this past tank.
But back to leaking injectors. I have read of a couple of ways to check this. If an injector is leaking bad enough then the oil will began to smell a little like gas as it would be seeping past the rings and down into the oil pan. that could also cause problems over time as you would have a cylinder being partially washed with gas on start up as well as fuel in the oil. Another would require pulling the plugs and looking for signs of one that could indicate it is running rich.. Another way is to attach or install a fuel pressure gauge so you could read the pressure right when you shut the engine off and then come back in a couple of hours and see what the reading is. It is my understanding that if all the parts are working properly, pump, injectors, and FPR, that the system should hold fuel pressure. So using a gauge will tell you if something is leaking but would not identify just which part. It's my understanding that the fuel pump should have a back-flow valve in it and then the FPR also will hold the pressure..
A sure way, but allot of work is to pull the fuel rail and pressurize the system and physically look for a drip...

I have thought about installing a permanent dash mounted fuel pressure gauge. I saw one where the sensor screws directly to the fuel pressure test port on the fuel rail and you plug the gauge harness into the sensor. That seems simplest and would help avoid having any unwanted fuel leaks.

I think I will try some injector cleaner in mine to. I used a can last year but really didn't notice any difference. seeing that my ECM is 30 years old, that is probably my next step..