She's dead, Jim.

[The Woj]

The newest addition to my Z family has given me it's first grief. It's a 1979 280ZX which I purchased with a 1987 Ford 5.0 in it. It was built on a bet by a naval engineer, and sold to me by his buddy who owns a machine shop and did a lot of the custom stuff. According to the previous owner the car has HO heads and a hot cam in it - but did not provide any further information on it.

 

I bought the car with the engine already swapped, and know virtually nothing about Ford engines. I drove the car from San Diego to the LA area without a problem, but upon arrival trouble began. To make a long story short, within the past few weeks it has been dying at idle - at first it would start to stall, then catch itself. But now, it just dies after warming up a little. So, I got a tank of gas last night (91 octane), and it seemed to be doing better, but today I started it and it died after maybe 30 seconds. Now, the starter will engage but it won't fire.

 

Anyone have any idea why it would start? Or a suggestion on where to start?

 

As I said earlier, I know very little about Ford engines and have only worked on cars for a short period of time. Thus, any information would be appreciated.

 

Thanks,

Greg

[Guest Phil1934]

Ford Duraspark ignitions are not very durable. I used to carry a spare box. Then the pickup went out. You can google how to troubleshoot, but I'd bet ign. box. (They'll want to know what color the connector is.)

[LS1 240Z]

is it carbed or fuel injected?

[The Woj]

Fuel injected, the entire engine including all the smog components are there as far as I know.

 

I'll look up the ignition problem, thanks. Anything else it could be? Fuel pump? The previous owner made sure to point out where the fuel pump was, kinda awkward and maybe a little suspicious?

 

Here's a picture of the engine:

[The Woj]

Found this posted here.

 

 

1983 Mercury Grand Marquis

Ignition System Malfunction When starting When warm

 

Q: I have a 1983 Mercury Grand Marquis, 302 v8 EFI, with the duraspark III ignition system. This problem just recently started.

The car starts fine when cold, but after about 4 or 5 minutes the car shuts itself off, and won't start again for about 10 to 20 minutes.

I had the ignition module tested and it checked out as good. I haven't had a chance to check the crank case position sensor yet.

Do you think that might be the problem?

I checked the ignition coil after the car stoped and there is no spark, but the engine turns over like it is trying to start.

And i found out that if i turn the key from off to start, about every 6th try i get one spark, and thats it.

Any suggestions?

 

 

A: Crank case position sensor???. I guess you mean crank shaft position sensor. That could be your problem. It has happened before.

 

 

So my next question would be: is it a good idea to add an aftermarket ignition and would that solve my Duraspark problem (assuming it is Duraspark)? Any system I install will have to be smog legal, too (I'm pretty sure there are many smog legal aftermarket ignition systems).

 

How hard is it to install aftermarket ignition?

[The Woj]

I might have found the problem. Whenever I hit the gas on the car (while it was running) I could hear the sound of air coming from the engine and the throttle response was relatively slow. This would occur for a second or two and then everything would return to normal. Furthermore, it sounded like it was being sucked into the engine. I knew this was out of place but just brushed it off as a peculiarity of the engine. I was reading through some troubleshooting and someone mentioned vacuum leak. I googled it and it sounds like what is occuring on my engine. The guy I bought the car from said he pieced together several intakes from mustangs to get it all working.

 

So, could vacuum leak be causing my problem?

[74_5.0L_Z]

First, because the engine is from 1987, it uses a speed density ECM. What this means is that the computer decides how long to pulse the injectors based on Manifold pressure, Throttle position and RPMs. If you have vacuum leaks (especially if the vacuum leak is in the hose leading to the MAP sensor), then the computer will be confused and the engine will not run correctly. This problem should not prevent it from running altogether, but would cause idling problems.

 

Have you pulled codes from the computer? That is usually a good place to start.

 

If you are unfamiliar with Ford fuel injection, then I suggest that you get Charles Probst's book on the EEC-IV engine management system used by ford. It is a very informative book, and provides a lot of insight into the operation and troubleshooting of these fuel injection systems.

 

The only item that I have had fail on my car is the TFI module in the factory distributor. These modules are known to eventually succumb to the heat under the hood. I looked into replacing it with a stock piece, but in the end I opted to upgrade to the MSD billet distributor that cames with new electronics installed.

 

 

http://store.summitracing.com/default.asp?target=/egnsearch.asp&N=400122

 

[The Woj]

Ok, so I tried to start the car again earlier, and it started just just fine. It was still almost dying at idle, and it was still having trouble with about 50% throttle from 1000-3000 RPM. I noticed that it almost died when the throttle was depressed.

 

I checked out the intake and all of the hoses and such around it, and I think I found my problem. Well, if it isn't the problem it probably should be.

 

I have included a couple of cameraphone pictures of my intake, the first shows the location I am talking about and the second is a closeup. What I found was a rubber large rubber hose clamped onto a smaller rubber hose in order to act as a turnaround. I do not know what these hoses are routing, but it seems like a shoddy way of doing it. If I remember correctly, the top hose had one or two sensors attached to it on the other side of the air filter.

 

 

On a (hopefully) unrelated note, the previous owner also mentioned that it was going through water pumps every few thousand miles. I think I found the astoundingly obvious reason why this is occurring, but would like to see if you all think the same way. Here is a picture of the lower radiator hose going to the water pump (the upper one is also like this at the connection):

 

 

Could the kink be causing the water pumps to be going bad?

 

Thanks for the help,

Greg

[Lason]

Check out the IAC sensor. Mounted on the throttle body its cylinder shaped on the front side of the throttle body. Take it off and check it for carbon buildup. 5.0's are notorious for these plugging up and causing hunting for idle and dying at idle. If its too bad just replace it but I usually disassemble them and clean them real good with carb cleaner.

 

Also when looking for vacuum leaks I like to use a spray bottle with soapy water and start spraying areas around the motor. If you do hit a vacuum leak with the soapy water the idle will clean up real quick for a second.

 

I highly doubt its your TFI module because when these do go out they go out and the car wont start at all.

[The Woj]

Well, I finally got back around to this project.

 

Thanks everyone for their advice, I think Lason hit the nail on the head. I unbolted what I'm pretty sure is the IAC and it seems pretty damn dirty:

 

 

Unfortunately, I got around to this at 11:00 PM so cleaning is gonna wait til tomorrow (I need to buy some carb cleaner).

 

My new question is, do I unscrew the two parts of the IAC housing for cleaning? Here's a pic of the screw(s) I'm talking about:

 

 

Also, I performed an accidental benchmark and now know this is probably my problem. When I put my manifold back together yesterday I forgot to reconnect the plug for this sensor, the engine was performing exactly the same (death during unassisted idle and trouble revving). One thing I did note after putting my intake back together was that my idle seems to be lower than it used to (around 650 RPM now, without IAC sensor too). I guess it should still be able to idle at 650, so I'm not going to worry about it.

[David K]

I would give so much to see your engine and trans mounts. You could make $$$ if you copied your engine and trans mounts and sold them as a kit. MANY people here on the Ford forum are waiting for someone to do that. I was going to do it, but i developed a pretty severe blood clot in my left leg on road trip. I just got out of the hospital yesterday after being in for 4 weeks or so. I lost lots of muscle in my left leg, and i need to go through rehab to walk perfect again. I would be your very first customer if you made a mount kit for the 280zx.

 

Heres my thread.

http://forums.hybridz.org/showthread.php?t=106398

 

I love your setup.

[Sven]

Woj, I was going to recommend the Idle Air motor to you, but Lason beat me to it. It sometimes makes all the difference in the world. Spray the hell out of it with carb cleaner, let it soak in, then spray the hell out of it again and clean that thing out.

 

Another thing to check/adjust is your TPS voltage(Throttle position sensor). They aren't even in spec from the factory half of the time. It can cause some odd idle issues, though not quite as severe as you describe. You'll need a volt/multimeter and piercing leads or straight pins. I found you a good description here:

http://www.muscularmustangs.com/tps.php

I stick with .98 because, when running, the voltage fluctuates a bit, and can nose above 1.00V. This will hurt performance, so... .98V. You pick up a few hp, and usually better throttle response after adjusting it too.

 

You also need to check and make sure the engine has the correct rotation water pump for the serpentine belt.They look the same. The older V-belt water pumps and the newer serpentine (yours) pump in opposite directions. It's a common mix-up. And fix that rad hose man, it's ugly!

 

One unfortunate thing I noticed is the plenum cover on your upper intake. Take it with a grain of salt, but you might not have an HO motor. The HO came in mustangs (duh), and Lincoln Mark VII's. Maybe the builder just used a spare upper intake or plenum cover. The way to know will be checking for roller lifters after you pull the intake. There is a 30hp difference between HO/non-HO. Not life or death, but the roller cam is nice when you start throwing $$$ at the motor to go faster.

*The duraspark is the predecessor to the TFI (Thick Film Ignition), and not the same thing.

EDIT: Doh, you say right in your post you have HO heads, sorry- not paying attention.

[The Woj]

I'm not too sure how much I want to modify this motor. I need the thing to pass smog every 2 years, and I'm not really in the mood to switch parts around to get it to pass.

 

As for it being HO, he said he put "HO heads and a hot cam," I did notice the upper intake has HO cast into it under the 5.0 plate.

 

I cleaned the IAC housing liberally with electrical contact cleaner earlier - it seems to have a lot of gunk plastered to it still, but there was a lot of dirty crap that blew out of it too. There was maybe a 1 x 20 inch layer of oil floating on top of the puddle of cleaner.

 

I really need to get a multi-meter. One of the guides I was reading said to test the IAC contacts on the harness and sensor side before cleaning. I'll just hope the cleaning works for now, I guess.

[Sven]

There are tons of performance parts for that motor with CARB EO numbers if that's your concern. There have been a few magazine article building emissions legal motors, it would take a little bit of looking. The easy way is to just throw on a blower. I'd definitely be interested in seeing more pics of your new car. I think you might have the first 5.0 ZX anyone has seen...

[The Woj]

Well, I drove the 500zx to La Habra and back (~22.5 miles either way) with the now clean[ish] IAC and it was giving me a little grief right after reinstalling it but a few hours later on the way home was doing great. I think the last bit of electrical cleaner must have dissipated in that time.

 

Once again, a big thanks for all the suggestions.