I pulled an 89 TBI out of a camaro and installed it in a 1985 chevy silverado many years ago. I am only mentioning this so you guys now what type of engine I'm working with.

I bought the truck back from a friend of mine not to long ago he owned it for many years and at least two of the years it sat inside a garage not running.

When I got the truck it was getting no fuel so I looked around online and found some people talking about an 89 ford inline pump working good for TBI engines so I bought one and installed.

Ever since I installed this pump I have had nothing but issues with major flooding. For months I thought I had injector problems. I couldn't afford to fix so it sat for about 6 months. I went to a savage yard and purchased a TBI unit from a 305 engine and the computer from the same engine. I installed both of them and had the same issues. So I swapped out the MAP sensor with another one I had laying around. No idea if it was any good just wanted to see some type of change in the motor. Still no change major flooding like crazy.

So someone mentioned coolant temp sensor I checked it and the plug was all messed up and so was the temp sensor even the plastic on top of the sensor was busted off so I replaced the sensor brand new. Still flooding like crazy. So someone mentioned okay what about fuel return line? I was well I never checked it so I checked that also. Found a plug on the 90 on top of the fuel sending unit so I had to pull the tank to unplug it. Some of the flooding fixed but still flooding to the point that it won't start.

I decided to check both the MAP sensor and the coolant temp sensor with an ohm meter. Found some guides online I tested the coolant temp sensor at 77 degrees F with my ohm meter on 20k it reads 2.99 no clue if that is correct numbers. My ohm meter reads 200,2000,20k,200k settings at 2000 it would read 1 so it wasn't really giving me any information.

So I tested the MAP sensor at terminal B it gave me a 4.8volt reading engine cold turned off with ignition on. At Terminal C it gave me a 5.0 flat volt reading engine cold and off with ignition on. So according to the guide I found the MAP sensor is fine although I didn't test it while the engine was at running temp and idling because I can't even get the engine to start and run.

I'm out of ideas unless that coolant reading isn't correct.

When I turn the engine over for about 10 seconds and I walk around to look at the TBI there is about a 1/16" of fuel sitting on top of the blades of the TBI if that gives you an idea how much fuel it's dumping.

 

Check your fuel pressure, see if you can rent a tester from auto zone, tell them its a tbi engine. The stock spec is 9-13psi. Maybe the return line is plugged up, take the cap off the gas tank & see if compressed air blow into to it easily.
Do you know anybody w/ a scanner? You can show live data, like the coolant temp & map data.
Check the ecm grounds, usually by the t stat & back of the heads.

 

The fuel return line was one of the issues I've done fixed it was clogged up on the 90 on top of the fuel sending unit. It fixed a small part of the problem it doesn't flood near as bad as before but it's still flooding extremely bad.

The PSI the pump is putting out should be around 50-70psi. I keep thinking it's the pump but from what I read online on other forums people are using them a lot for TBI conversations and having no issues with the extra psi since the regulator in the TBI should regulate it down to whatever pressure it needs. The guy from TBI chips claims he runs more extreme psi pumps then that on TBI without any issues. He says it's not the pump.

I never got around to hooking up the OBD wires and actually putting it in. I'd have to jump some wires and put a light bulb in place in order to pull codes which I have done before. I may have to try that again sometime.

 

Check the pressure anyways, if you work on efi engines a fuel pressure gauge should be in your toolbox.

 

I have a fuel pressure gauge of course but I don't know how to check to see what the actual TBI unit is putting out. I can check the pressure before it goes into the TBI but I don't see what good that will do. That will only give the fuel pressure the pump is putting out. Is there a way to check the pressure that the regulator is allowing through?

 

From the pump to the regulator, this is pressurized. The pump gives flow, the regulator gives it the psi.
From the outlet of the regulator to the tank is unpressurized, meaning no restriction at all.
The injectors don't make pressure, they open & close.
What if your pressure is 50psi & its supposted to be 12psi, you WONT KNOW TIL YOU CHECK IT.

 

Could be an old fuel pressure regulator. After many years of service the diaphragms get old and brittle (you can see what mine looks like in my VRFPR thread) and fails to regulate the fuel pressure correctly.

 

50 to 70 psi is way too much pressure for a tbi injector. period.

 

That's exactly what I have been trying to tell the guy from TBI chips that I email back and forth. He's been telling me for months its not the pressure and it's not the fuel pump. That he uses them all the time on TBI engines with the factory TBI regulator and never had issues.

Well I installed a regulator today and set the pressure around 16psi and the truck started right up and runs good now. That goes to show you that some people just don't know what they are talking about. He seems like a very knowledgeable guy. I don't mean to talk about him but because of him my truck has been sitting in a garage for almost a year with this same problem. I have changed all kinds of parts out and tested multiple things but I left the pressure and the pump alone because he kept telling me it's not that.

I wouldn't have even installed that pump if I hadn't read on some jeep forums or something about guys putting TBI's in jeeps and using that exact model fuel pump and it suppose to be a good one for TBI. All I know is it's not good for my truck it has caused me nothing but headache since day one. I'm pretty disappointed that all this time it has been too much pressure.

 

Look, your first mistake was the wannabe "Tuner" you consulted, Brian may be able to tune,...but his dyno results don't reflect that.

Get TunerPro RT 4 http://www.tunerpro.net/downloadAppLegacy.htm

To rape brians chip you'll need some Moates gear, I would NOT waste your time, better that you start clean slate.

You could get the best from your combo by learning a little, and using a tool like the EBL,

http://www.dynamicefi.com/

 

Well I wasn't buying a chip from him I asked him some chip questions a couple years ago and keep in touch once in a while if I have any issues with TBI I consult him and forums I find. If I decide I want some tuning done I plan on buying all the stuff to tune myself. That's one of the main reasons I keep pushing this TBI so much. I want to learn tuning. I've had so many of my friends try to talk me into putting a carb. I know right now I can install a carb and drive it any where but tuning sounds fun and it sounds like something I'd be really good at once I actually get into it.

I read a lot of the information on the thread called Come in for a free tune. I'm pretty excited to get my truck on the road soon. Tagged, inspected, and all that good stuff so that I can purchase the items needed to start reading that thread and learning to tune. Could be tax session right around the corner before I can afford to do any of that but it's looking a lot more promising now that I have actually narrowed the problem down.

 

Well I'm completely confused about what it going on. I used a regulator before the TBI and was able to get it started and running. Well I noticed when I tried to push WOT I'd get a little over half throttle and the engine would bog out like it wasn't getting enough fuel or something.

I tried to crank the regulator up some and it didn't help anything. So I pull the regulator off and it started right up without any issues where before it was flooding like crazy wouldn't even start. Still has a nasty bog when trying to go WOT.

So I decided to do some investigating thinking maybe there is a bend or something in the fuel line some where. As I was tracing the fuel line down I get close to the headers and see that my o2 sensor wire coming off the o2 sensor is sitting on top of the headers and is melted like crazy. So some how the o2 sensor got unplugged and hasn't been plugged this whole time. So I get another connector and fix the issue and plug it back in and didn't seem to make any different in how the engine runs.

With these symptoms do you guys think its the o2 sensor? I dunno I don't understand why it would bog out before the o2 was plugged and still do it. Seems to me like something would change.

I think I need to just go through and change out ALL the sensors since they are all pretty old and maybe that will fix my problem. I'm out of ideas I'm so sick of my vehicle being useless.

 

I haven't read your entire thread but... you do not need an exteranl regulater with a TBI. The regulater is in the injector pod!

Now that you have a regulater and things have changed we know you have fuel pressure issues. But until you can get a fuel pressure reading we won't know. You check fuel pressure anywher after the pump and before the inlet to TBI.

Also when you get a fuel pressure reading if it is over 13 PSI look for something obstructing return line again. If you have an obstruction and 2 psi on return line your feed line also goes up 2 psi. If that is OK you could have a bad diaphram or broken spring in regulater.

Here is a link to ohms readings for CTS sensor.
http://www.gearhead-efi.com/Fuel-Inj...erature+Sensor

 

Just to fill you in, he fixed the fuel pressure issue but it looks like a major part of the problem could have been due to the O2 sensor wire getting melted by the headers.

 

Well it was just the connecter itself that got melted but I fixed that and the o2 sensor is plugged back in. It just seemed like plugging it in didn't make any difference. When I noticed it melted and unplugged I freaked out thinking that was the problem the entire time.

 

Sorry about the confusion on the fuel pressure. My fuel pressure reads around 16psi or so without the aftermarket fuel regulator on. After pulling it off it didn't change the pressure at all.

For some reason when I put the aftermarket on it started to run and stopped flooding like it was doing. So I thought that fixed the problem. After running it on and off for a day or so I didn't really give it a lot of fuel because it had been sitting up a while I didn't want to mess nothing up. So I let it run at idle for 10-15 minutes at a time and just gave it maybe half throttle here and there and it seemed fine. I never tried WOT. It wasn't till day before yesterday I tried WOT and it kept bogging like it wasn't getting enough fuel or something.

I decided to pull the aftermarket regulator back off and the engine started just fine without flooding. Made no sense to me at all why would it flood before but not after? I figured well maybe the o2 sensor was causing the issues since it wasn't plugged up before and now it is. The gauge I have on reads around 16psi.

I've tested the coolant temp sensor and the MAP sensor and both came out to be good. The CTS is brand new I replaced it when I first started having these flooding issues I found the plug broken and the top of the CTS was broken too. I fixed both of those problems and it didn't solved anything. Nothing changed at all.

I replaced the TBI three times already with different ones. I thought it might have been a regulator or injector problem so I have already tested that.

I've also replaced the control module when I first got the truck back from a friend.

I've also replaced the computer it used to have some 2.8L v6 computer how that even got on the car in the first place I dunno. I put a 7747 computer on it since I wasn't able to find the original one at the savage yard I looked at. I heard the 7747 was a better replacement anyways so I didn't worry about trying to get the original.

I've tried all sorts of things. I had a clogged fuel return line that I fixed also. I'm out of ideas I don't know what is going on I feel like this truck has a freaking curse or something. lol over a year now and still it sits not running correctly. When I start it runs perfect at idle so smooth you can't even see the engine move. As soon as you give it some fuel pretty hard it bogs out like it just wants to die.

I put it in gear and try to take off down the road and it bogs out under pressure. lol this truck is evil I think it's possessed

I will try to make a video of it in a little while. I'll start it and let it run and try WOT so you guys can actually hear it sometimes that helps to figure out an issue. Explaining sometimes isn't good enough.

 

It sounds like you are testing the fuel pressure under no load as in idle. I would run the gauge to windshield with hose and hose clamps duct tape and see what the FP is under load or during the bog. have a passanger read pressure not you. That will rule out lack of or too much fuel...

ps technically is is possible to overpower the return line causing excessive FP. I think a Walbro 200 series will do just that.

If the 02 is kaput you may have been ruunnin on the calpack or limp mode. If not the correct calpack it may cause rich condition. Mine did any way. I had a V6 calpack with a 350 engine. have you verified the prom and calpack are proper for the 305 auto ?

 

Crazy idea but what if it's the injectors?
I've also heard of faulty gaskets from anywhere on the intake creating that problem. Makes sense when you consider that a vacuum leak would cause a reduction in the intake mixture velocity and quality of mixture. Maybe your FPR diaphragm is old?

Your problem is so oddly persistent that I'm really shooting from the hip with suggestions here

 

Well I'm running a pump many have said they run on TBI engines up to about 300 hp without any issues. It came off an 89 Ford F150 they had an inline pump that suppose to do 40-70psi or something in that ballpark I can't remember exact numbers. It suppose to be not too much for a stock TBI or even a modified TBI.

 

alright guys first video it's hard to hear what is going on I tried to record it under the hood but with the wind outside blowing and the wind from the flex fan, all the noise from the engine bouncing around it's hard to tell anything but at least you can kinda see what the fuel is doing in the TBI.

http://www.youtube.com/embed/X9Xkuv_E6dk?hd=1

The second video is done inside the truck where you can actually hear it bog out and backfire. I didn't really hear the backfiring till I really got on it good for the video so now I know it's backfiring.

http://www.youtube.com/embed/9iZqLtbE1uc

 

injector inspect visually at idle with or without timing light. nice clean conical spray no dripping.

vac leak due to gasket is a high idle.

 

I thought it might have been a vac leak so yesterday while it was idling I sprayed around the bottom of the TBI with Carb Cleaner and around each connection of the vac hoses and couldn't find any leaks.

 

CE light functional?

 

I hooked one up a while back just for testing I haven't tried to pull any codes but I'm sure the light is still hooked up. I will check to see if its coming on. I'll have to get my diagram back out to make sure wiring is correct on the obd.

 

I've done that and found no leaks! But when I used starting fluid it found vacuum leaks! Short squirts, long arm, outside no breeze. Works great but also very dangerous if you find spark! WARNING!!! Please be careful...another way that is safer but still not as good as starting fluid is a propane soldering torch, unlit of course but wide open and check all places that could have a vacuum leak. Also pinch shut vacuum line to brake booster? Plug PCV valve? Lot's of places to find vacuum leak and some can not be found under intake manifold inside engine...

But! 16 PSI, on an accurate gauge is 3 psi to high for a stock TBI engine. Unless you built the engine over stock and have an adjustable regulater and set it that high. Pull your return line at TBI and run the return line into a gas can and check pressure to see if it drops. Should be 13 psi stock. If the gauge is close to accurate. So you may be back to a faulty regulater in injector pod. 3 extra PSI is a lot of fuel in TBI!

I have used the pump you have several times with no issue of to much pressure. HTH!

 

a functional CE is " key on engine off a quick blink followed by solid on engine not runnin".

OBTY did you pull a plug and check for richness? Overly rich will throw a code after 10 min of driving.

 

Well I put the aftermarket regulator back on because it has the gauge I use to check fuel pressure and it fixed the problem. It all ***** down to fuel pressure. Its getting too much. I don't see how it could be the fuel pressure regulator on the TBI I mentioned in earlier post that I changed the TBI out three times already. All having the same symtoms. I just think the pump I have is just too much but for right now I'll leave the aftermarket regulator.

By the way makes no sense to me but the regulator all the way open it still fixes the problem. I checked pressure at WOT like you guys asked me to do and it goes down to about 10-11psi at WOT but sits around 16psi while idling or just key turned on. But it does this with or without the regulator like I said even with the reg all the way open it still fixes the problem. I can punch it to the floor and it raps like a bat out of hell now with no hesitation. I guess I know now not to ever use one of those pumps again. I didn't want to swap out the gas tank to a newer 87 model so I could put the pump in the tank. Seemed like too much trouble to me that's why I searched around for a few days online for a good inline pump and lot so of people said that pump. I dunno guess it's not good for my application.

It's more my fault then anything else. I was always told a regular fuel pump for TBI will make the engine run good just never great because of it never putting out the max psi the injection can handle. I was looking for a higher psi fuel pump so I could get a constant 13psi all the time even at WOT. I used to run the Airtex E8153 pumps that seemed to work just fine. I've never tried to use a gauge on them to see if they held a good psi even at WOT. I just assumed they didn't since the pump says 9-14psi. If I would have just stuck with that pump for less money then I spent on the 89 ford pump I would have been driving my truck for over a year now. Oh well lesson learned.

 

whoa. did you say you put the regulator BEFORE THE TBI??????? that is the wrong place. it needs to be on the return side so the tbi will get the pressure. i bet if you move it to the return side your problem about the bogging will go away.

 

That is strange and I can't figure out why either? Since it is wide open and pressures are the same the only thing I can think of is it is restricting flow.

The pump you have has been used a lot with no issues but it is not correct for your TBI engine. People use it because it is a cheap pump. I know a site that pushes this pump and there is a lot of mis information there...

Carter makes a correct external in line TBI pump. NAPA has them PN5000 or PN5001 I always forget, one is TBI one is TPI. Excellent pump built proper for TBI but in line, not in tank.

Did you try fuel pressure with return line from TBI to a gas can? It will prove or disprove a restriction in return line which would raise your feed line pressure!

Since this is a conversion what size line did you use for return?

 

It was actually bogging because it was getting too much fuel. I thought it was acting like it wasn't getting enough. It just couldn't burn the fuel it was getting. From what I been told the fuel gauge or regulator goes after the pump any where before the TBI or injection. I thought it would need to go after the TBI myself but I was told that's wrong.

 

He's already to high a pressure. If he restricts return it will go higher.

TBI has a regulater! It does not need one on either side. If you need to change pressure then make or buy an adjustable regulater for the TBI unit. It is mounted in injector pod.

 

It's whatever size is normally factory on a 1985 Silverado. That's what the engine is currently installed in. I think the one coming from the pump is 3/8 but the return looks a bit smaller. I haven't tried to hook a gauge on the return side yet to try that out. I ran out of daylight. I may do that tomorrow just to see what it reads. I just know right now with the regular in place it's running really good compared to what it was. It still has a hiccup here and there but after running rich a while I'm sure the plugs are a little fouled and maybe even the o2 also.

 

It is wrong because you would be adding a regulater, after the regulater! Return line should be 0 psi if you check the pressure there.

 

I had actually modified a pod a while back that I had planned on using on this truck eventually. I just don't have anymore gaskets right now in order to swap it to that mod pod. I drilled it out and slotted it so I can adjust it. I was hoping to crank up the pressure some to make it better but after seeing how it's reacting to this pump I don't think it's a good idea. lol

 

THE REGULATOR GOES ON THE RETURN SIDE... PERIOD!!!!!!! if it will run and is bogging now at a higher idle or off idle it is because the tbi is not recieving the pressure it needs. the adjustable external regulator is just that ----adjustable---! put it on the return side and set the pressure to 13 psi and see what it does.

 

I tried looked up the PN5000 and PN5001 on NAPA website and google and getting a few results of people talking about them on forum but NAPA doesn't give any results or anything on either of those pumps. Maybe they are discontinued or they changed the numbers?

 

i have an intank TPI pump. it is rated for 40 psi. a factory tbi reg will control it. but as stated above. the regulator needs to be on the return side.

 

That's actually the pumps I normally run but I was trying to do something similar inline but was having a hard time finding one around 30-40psi inline closest I could find at the time was that 70psi one. I use the 94 corvette pumps on TBI on many different ones and never had issues they are awesome.

I was considering using one of the Walbro pumps but there were a lot of different choices on ebay with different LPH and I wasn't sure which one I would have needed for my engine. Almost all the listings didn't display any type of pressure the pumps put out. I contacted Walbro from email asking them a pump they would suggest and for some reason they couldn't even point me in a direction so I gave up on them and ended up with the 89 ford pump. This truck has been a nightmare I can tell you that. lol Nothing has gone right since I owned it.

 

Heres a picture to help you figure it out. Use an open end wrench to measure the line diameter.

 

Wow I didn't even realize the gauge goes on one side and the regulator on the other side. The el cheapo regulator I got off ebay has a build in gauge on it. I guess that couldn't even get me an accurate reading anyways. I'll have to see if I have a gauge laying around that I can install separately.

 

And you used the EP241? Those put out between 50 and 70 psi

@JoeBob- be sure to check that FPR periodically. I thought about getting one like that but read some accounts of diaphragms breaking

 

i believe that his regulator placement is the crutch right now.

 

So you are currently at idle 16 lbs and at WOT 10-11 lbs?

Does anyopne know if that is possible?

I never checked my FP at WOT. I dont think I ever needed to. Maybe I will next season. This past fall I saw 105% DC. So upped FP twice once seeing 90% and then 85%. So i should be OK now.

Any way i dont see hiow his FP can decrease as he is using a larger than needed pump.

May want to run stock GM reg and spring.

 

Really should not happen when pump is more than needed. Yes it can happen with correct pump. Pressure to high, then WOT not enough flow would drop pressure.

He may have voltage issues to, or grounding issue, which will change fuel pressure. This is a conversion as well, so more to look at then just an EFI system that came on car.

Also the information above on this Ford fuel pump PSI is wrong. IIRC it is not MPFI pressures, closer to TBI pressures but I have not been able to find specs I used to have on it.

Still all this makes no sense as his pressure is still to high for stock TBI regulater. But he has said he changed TBI unit as a whole and pressure stays the same. This is why I have been trying to get him to run a fuel line from return port on TBI to fuel can and check fuel pressure. Or check pressure of return line, if gauge is possible to see low numbers. Return line pressure should be 0. Feed line will go up 1 for every 1 PSI in retrun line. He is 3 to high. Stock TBI spring with adjustable regulater only goes to 15 IIRC. So we still have 1 PSI that is not even possible but could be the gauge.

 

It's kinda hard to tell from the gauge to be honest the reading I see could be 14-16 it's hard to tell the stupid gauge goes from 1-100psi and it goes 20,40,60,etc and in between each number is like 6 marks or something so it doesn't even by by 5's or even a number that is easy to read. I'm guessing it's closer to 16 then 14 but I can't be positive.

 

I was able to get my fuel pressure exactly where I need it by putting the aftermarket regulator on the return line. Thanks to one92rs suggestion. I set the pressure around 12-13psi but the gauge jumps around bad. Not sure if it's because of fuel pressure or engine vibration. It runs even better then it did before on the other line and it has really good response now. That pretty much fixed everything. I installed a different gauge on the other line to set the pressure. It's a Mr Gasket 0-15 psi gauge but like I mentioned it jumps around like crazy. I did notice when I punch it to the floor from under the hood the fuel drops to 0 on that gauge then went I let off it goes back to around 12-13psi. It runs really good so I guess for now I'll just leave it alone.

I have timing set to 8 degrees advanced not sure if that is too much or not but it surely has some good response at 8 degrees advanced. I thought I read a while back that even the stock TBI's run their best at 8-12 degrees advanced even without a cam. I swore I read that some where but I could be mistaken. Maybe you guys can enlighten me on that. I wanted to try that ping trick but I live in south texas there is no hills here to do that test. lol

 

That is all just so wrong I don't know where to begin?

Now your playing with fire as well. If you add 8 degrees timing at idle with timing wire disconnected then you have to put 8 degrees in Initail Timing in your bin/chip so it takes it off the top. If not, at WOT high RPM you will have 8 degrees to much and knock/detonation or even fire the next cylinder. Add to that your fuel pressure drop mentioned above you'll be running LEAN...

The outcome is not going to be good... bye bye motor.... really don't do this...

 

Maybe that's what they meant setting it with tuning I'm not sure. It's been a good while since I read that.

 

HE IS NOT PLAYING WITH FIRE. it is on the return side and running well. LIKE IT IS SUPPOSE TO BE. i got my timing up to 6 before i got knock. but it was only with the a/c on and under a load. try it and see what it does. listen for the rattle can noise. not sure on the pressure drop. voltage maybe. take it out on the road and see what she does at wot. i have seen ghauges jump around about 2 or 3 psi. never a problem. i have also had gauges tell me i had 4 psi and she still ran. take tbi gauges with a grain of salt.

if you really want to know check out this link
https://www.thirdgen.org/o2tuning

 

I don't know a lot about the TBI engines but I do know I've run advanced timing on many engines without causing any harm. I normally don't go over 4 degrees advanced but I used to read a lot of forums and such about the TBI engines and I'm pretty positive I read some where they love to be advanced and as far as I know as long as you don't go too much it won't harm anything. I'll probably lower it down to 4 and go from there instead of starting so 8. I haven't put it under any load yet I ran out of daylight before I was able to put it on the road and see what it would do.