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Old 08-18-2013, 06:32 PM   #1
caddymatty
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85 el camino w/ tpi

Hi everyone I am brand new to these forums and very wet behind the ears when it comes to working on cars. So of course I jumped right in and got a couple vehicles that I really love and I am going to learn this stuff if it kills me.

With that said the other day I picked up this el camino. It has a 1986 tuned port injected motor with the 90-92 speed density system. The el camino has no performance mods other than hedman full length headers and exhaust. As far as the installation goes the person told me that he put the tuned port injection fuel pump into the stock el camino tank. The truck seems to be starving for fuel when I try to start it and also when I come to stops.

When trying to start it I must put the key into the on position first,listen to the fuel pump pressurize then give it a try. It never seems to start for the first few times and everytime I must go back to off position, back to on,listen to pressure blah blah. It seems that it is a priming issue perhaps?

When I am driving down the road sometimes when I come to a complete stop it will stall. It seems to not be as bad when the tank is fuller but it still happens then once in a great while. Not sure if this is from sloshing in the fuel tank or some other reason.

I am not sure exactly where to begin but I want to try and problem solve this on my own. Where to start is the question? Do I begin with things like the fuel pump relay or is this just something a mechanic is better off problem solving for me.

Thanks guys I really love this forum been soaking up a lot of info.
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Old 08-18-2013, 06:52 PM   #2
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Re: 85 el camino w/ tpi

Sounds like a priming issue. Check fuel pressure running. Pull the intank assembly and check to see if the hose that connects the pump to the sender assembly is loose or leaking. Check to see what the fuel inlet sock looks like....
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Old 08-18-2013, 07:38 PM   #3
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Re: 85 el camino w/ tpi

So my first option after I check the fuel pressure is to pull the fuel pump out of the tank? What will I be looking for when I check the fuel pressure to know if the tank would be the first choice to check or something like fuel pressure regulator or fuel injectors?
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Old 08-19-2013, 04:30 AM   #4
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Re: 85 el camino w/ tpi

Check/repair/replace fuel filters...I would be interested in what the pressure is, psi is important with efi. Secondly, the symptoms you're describing sound familiar to what my GF's car was doing. Fuel pressure was minimal when checked, but responded a little when vacuum was applied to the regulator, we replaced the pump with a 255 walbro. Put the tank back up and it wouldn't start (New pump was more efficient than old 140k pump). We could hear the pump priming...so pulled the tank back down, checked the clamps and they were tight. The hose seemed a little old, so we replaced it,and put the tank back up (car fired right up.) The car used to take cycling the key to get it to prime enough to fire, and acted similar to yours. Now, turn the key, it primes and fires right away and has a better top end. What I'm saying is that old IROC unit is old. Check your fuel filters, check the sock on the pickup for the pump and also check the condition of the hose intank between the fuel pump and sending unit.

Most efi pumps will fire a car if going bad for awhile... when you are putting the engine under load that's when its noticeable that the pump is bad, the vehicle wont pull grades easily like it used to. The FP relay is probably fine, if it weren't you wouldn't have fuel. Injectors are probably fine too, the car runs. Sound fuel delivery related.
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Old 08-19-2013, 09:32 AM   #5
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Re: 85 el camino w/ tpi

Thanks that sounds very helpful, also hearing you have a similiar incident with the gf's car was pretty reassuring as it sounds about the same.

I am gonna check the fuel filter first today and if that doesn't work probably move onto the tank.
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Old 08-19-2013, 11:11 AM   #6
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Re: 85 el camino w/ tpi

You need to see at least 43 PSI at the rail. I agree that is sounds like the pump is laying down, or the line is thrashed. To fix your fuel slosh problem, hit up Rock Auto or something similar and get a fuel tank for an '87 4.3 El Camino. They were TBI, and the tank will be baffled. If you are dropping it anyhow, now would be the time to do it.
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Old 08-19-2013, 02:19 PM   #7
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Re: 85 el camino w/ tpi

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You need to see at least 43 PSI at the rail. I agree that is sounds like the pump is laying down, or the line is thrashed. To fix your fuel slosh problem, hit up Rock Auto or something similar and get a fuel tank for an '87 4.3 El Camino. They were TBI, and the tank will be baffled. If you are dropping it anyhow, now would be the time to do it.
I agree. I would find a baffled tank for a 4.3 TBI and put a new TPI pump and filter in it. Was this a running car or an incomplete project that you finished? Are you getting any codes set? Are the lines in good shape? Did he/you swap to FI hose or does it have original rubber fuel line?
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Old 08-19-2013, 03:23 PM   #8
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Re: 85 el camino w/ tpi

I believe this car had a 6 cylinder tbi in it from 85 or were they not offered then? This was an incomplete project that I picked up. I have gone to auto zone and a shop and neither one has been able to read anything from the computer. Something about it having an older plug on it. It has an 86 tuned port motor in it with the 90-92 speed density computer. The person I bought it from says it should read and he had done it recently before but who knows. I am not sure of the fuel lines I assume the rubber lines would be no good if thats what it has?
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Old 08-19-2013, 03:26 PM   #9
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Re: 85 el camino w/ tpi

I am changing the fuel pump and filter to see if that works. Fingers crossed
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Old 08-19-2013, 03:54 PM   #10
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Re: 85 el camino w/ tpi

You can pull codes with a paper clip shorted between the "A" and "B" terminals of the ALDL. That puts it in field service mode. You will see code 12 flash 3 times, then what ever codes you may have 3 times, then 12 again 3 times.

Not sure of the first year for TBI, but if you are having fuel starvation problems while driving with less than 1/4 tank, I bet it is not a baffled one.
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Old 08-19-2013, 09:07 PM   #11
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Re: 85 el camino w/ tpi

Here is a little update. Went and changed fuel pump and filter at a shop since the landlord wasn't keen on me working on it in my apartment parking lot. They go and change of course first and then decide to test the connector to the pump. The connector is only getting 8 volts so obviously we got a bit of a wiring issue to deal with. They seem to think their is also something clogging the line so gonna make sure those are cleared out as well.
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Old 08-20-2013, 08:28 AM   #12
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Re: 85 el camino w/ tpi

Your best bet with a TPI is to get an aldl cable and a laptop or a scanner first (and a fuel pressure gauge)..Then you would have known instantly that your voltage was low at the fuel pump.
Try the Thirdgen website http://www.thirdgen.org/techboard/tpi/ there is tons of information there.
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Old 08-20-2013, 08:41 AM   #13
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Re: 85 el camino w/ tpi

I would have liked to do that but as I had mentioned they cannot get a communication with the computer for some reason. I went to autozone first and they tried to hook up there computer to it and it wouldn't read, the person said it was because it had an older scan connector but the read would have to be for a newer vehicle(It has 86 305 tpi but has the speed density from the 90-92 not sure if thats what he meant). He then told me that the only way to scan it was with an obd1 scanner. So I asked wheres the closest shop with it and ended up where I was. They put it on the scanner and couldn't get a read either for some reason. I told them even when they scan it to make sure its for a 92 camaro.

Bottom line now I am confused and definitely not a fan of these guys just trying all types of stuff especially if the scan could just solve it all. My question is how do I get the computer to scan at this point?
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Old 08-20-2013, 08:55 AM   #14
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Re: 85 el camino w/ tpi

Test with the paper clip as Jonboy suggested..To see if you get the code 12. If not you may need a new one. TPI troubleshooting starts at the computer. You need to establish communication to be sure it is functioning properly. First place to start would be to check that it is properly grounded.
They can be tricky sometimes to connect to..They are nearly 30 years old.
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Old 08-20-2013, 08:59 PM   #15
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Re: 85 el camino w/ tpi

Well just to give a quick update. Got the car back having done the fuel pump,filter, sock valve and its running like a totally different car. So glad thats all it was. Gonna give her a tuneup tomorrow or next day and should be in business. Thanks everyone for the insight I really appreciate it.
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Old 08-21-2013, 03:11 AM   #16
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Re: 85 el camino w/ tpi

All code readers people use now are obd2 and that tpi set up is a early odb1 system and the newer stuff won't read it at all.I'm glad to hear you got it running good now its nice to see g bodies still driving around not on huge wheels.If you need help finding parts or ideas what you can do to it let me know i know a ton of sites and info on them.
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Old 08-21-2013, 04:23 PM   #17
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Re: 85 el camino w/ tpi

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All code readers people use now are obd2 and that tpi set up is a early odb1 system and the newer stuff won't read it at all.I'm glad to hear you got it running good now its nice to see g bodies still driving around not on huge wheels.If you need help finding parts or ideas what you can do to it let me know i know a ton of sites and info on them.
Thanks man definitely helpful and I will surely be seeking advice from you in the future.

As it stands its weird it rained hard last night and this morning and I had trouble getting her going again. Hoping it was just from the rain but who knows, wondering if their is an underlying factor still there. After it got warmed up it was fine wondering if maybe something with the fuel regulator diaphragm or along those lines.
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Old 08-23-2013, 02:20 AM   #18
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Re: 85 el camino w/ tpi

This might sound odd but check the distributor cap,If its cracked it could be letting moisture inside it. Or worse case hit up http://www.thirdgen.org/ its 3rd gen f bodies and they know the tpi system better then any of us i bet.
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Old 08-23-2013, 07:05 AM   #19
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Re: 85 el camino w/ tpi

OBD 1 is very user friendly. a paper clip and the ability to count a WORKING light bulb flash its code series to you.... they printed books on how to hotrod your TPI motor. that book and a multi meter will solve a world of issues for you. if your new to this, then it would be a very good read. the next thing it needs is a swap from speed density to mass airflow ( simpler system) parts can be sourced at junk yards and local parts places cheap.
I ran one in my jeep for years you learned what parts would always fail. carried a spare of said part and eventually learned the symptoms on impending failure. that being said.. there is a ton of help here on the BB.
Good luck n have fun.
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Old 08-26-2013, 02:29 PM   #20
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Re: 85 el camino w/ tpi

Ok guys here is an update. As I mentioned I am not a mechanic so I am trying to piece together this information to provide to you and hopefully can set me in the right direction.

The other day I had the fuel pump changed and it greatly improved how it ran and it would start right up. Now the next day when I attempted to start it cold it took forever. Once it has been started if you attempt to restart it in the first 30-45 minutes no problem fires right up, if not then its back to cranking over multiple times and doing cycling of the key.

Now I went back to the mechanic who replaced pump and now he says that the regulator has gone. It is an adjustable fpr and he showed me when he attempts to adjust it that it does nothing. Now he says if this is replaced it would solve all the problems. He states that the diaphragm is most likely no good and that this is the reason for cold startup problems. He says it will not hold pressure due to the diaphragm being bad. What he did in the mean time is disconnect the vacuum line from it. Now this did not help with the startup but the driveability is back to perfect. It runs great once started so that little bit of extra psi helps. Now with that said this is why he says it drives better now yet doesn't help at startup because the fuel still flows through the regulator but it doesn't have the vacuum that opens up the diaphragm to allow in the extra fuel it is just doing it all the time. In your opinion with what I have mentioned is a fuel regulator going to permanently solve the driveability issues as well as the starting issue. If you spray cleaner in the throttle body it will start right up so obviously still not getting the fuel pressure at startup.

Thanks for taking the time to help me out with this guys, I really appreciate it.
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Old 08-26-2013, 02:36 PM   #21
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Re: 85 el camino w/ tpi

You would be able to tell with a fuel pressure gauge in about 2 minutes...

Could also be the CTS..No cold start enrichment. Much easier to change then a FPR.
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Old 08-26-2013, 02:48 PM   #22
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Re: 85 el camino w/ tpi

The fuel pressure was reading about 30 psi and it wasn't able to be adjusted. How would I know if its cts or fpr.
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Old 08-26-2013, 02:55 PM   #23
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Re: 85 el camino w/ tpi

It should be 43.5 ...So it very well may be the regulator if the pump has been changed already.
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Old 08-26-2013, 03:01 PM   #24
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Re: 85 el camino w/ tpi

[IMG][/IMG]





Ok so here is a picture of the fpr. I was told I need to get an aftermarket one anyone recommend one that isn't too expensive. Also here is a picture of the plug coming from my computer. All the mechanics I have gone to can't get a reading from it. I was told this is an older connector and can't communicate with it.

Is this something to do with an 86 motor with speed density on it. Is this just the completely wrong connector or I have no clue whats going on. I had someone try to read on an obd1 with no success. Maybe the people checking it out were a bunch of magoo's I am unsure.
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Old 08-26-2013, 04:07 PM   #25
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Re: 85 el camino w/ tpi

All you need to do is get a diaphragm.... that is an aftermarket fpr. The connector you are showing is the right connector, follow the wiring and make sure its intact. My TPI is not managed by the stock computer it was also an 86. I run speed density with a Holley efi box eliminating the maf. As long as you are set up (ECU wise) to properly run speed density it doesn't matter if your TPI was originally a MAF setup.
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