Got a few questions for you guys.

So I have a 1989 formula with a 305TPI boat anchor that has 160K miles on it that has been acting up lately. it is my daily driver currently

First thing wrong with it is it smokes ALOT on any kind of startup. Hot cold everything. I'm fairly certain its the valve seals and I do plan on putting new ones in this winter

Second problem is a little weirder. It will die when put in reverse or drive after getting up to operating temperature unless I give it a little gas before I shift.
Usually this is because of IAC problems but I've gone through the entire throttle body assembly cleaned out passages and checked for vacuum leaks and it all looks good.
I also reset the minimum idle. no change.
could this be a EGR valve being stuck open? my poor gas mileage would also point to the EGR.

I have taken a data log with tunerpro and my BLMs while idling are pegged at 108. it goes to 128 when I give it some gas. Is this normal or should it always be at 128?

The car still runs pretty good because I've changed a lot of the sensors and fuel delivery components but the above issues are probably contributing to my poor gas mileage so I would like to resolve them.
Any help would be appreciated.

here's a data log I recently took if any of you want to look at it.

 

What injectors are you running?

The BLM and INT should ideally be around 128 all the time. Nothing is perfect so they will fluctuate but pegged at 108 is not right.

GD

 

I looked at the data.

The reason it goes to 128 when you accelerate is because it's still "learning" at those conditions. At idle, you've spent enough time at idle speed that the BLM has followed the Integrator down to the minimum. The integrator (record of short term fuel correction) follows the O2 sensor. The BLM (record of long term fuel correction) follows the integrator. If the O2 sensor pegs rich and stays there (it's supposed to be bouncing around between rich and lean), the INT will start dropping precipitously. If the INT stays low for a long enough period of time, the BLM will start to drop. Once the O2 sensor sees that the fuel has been trimmed back to ~14.7:1, the INT will rise back up to 128 and the BLM will stop dropping. The thing is though, if you pass through various operating conditions quickly liked during acceleration, there isn't enough time for all of this to occur.

But based on what I'm seeing, I suspect that if you held the throttle at a particular RPM and load long enough, the Integrator will drag the BLM down to 128 as well. As you move into different operational conditions, I can see the Integrator dropping... so over time, the BLM will eventually get there as well.

You most likely have some sort of fueling issue causing an abnormally rich condition. If it were ignition like a bad spark plug or bad plug wire, you'd have unburnt mixture exiting the cylinder containing unburnt oxygen, which the O2 sensor would read as lean, thereby causing the INT and BLM to rise, not fall.

Basic things I would do first...

Inspect your fuel pressure regulator... look for a disconnected or broken vacuum line. That'll cause the regulator to put more fuel into the engine.

Could be a broken internal diaphragm. Without starting the engine, prime the system by turning the key on. After the fuel pump shuts off, does the system hold pressure? Or does the pressure drop quickly? This could also be a bad injector(s) leaking fuel as well (at least one on the driver side since the O2 sensor is seeing it).

What's the story on your injectors? Original Multecs? Could be a bad injector dumping in too much fuel. At idle speed in park, unplug one injector at a time on the driver side and see what the BLM does. I suspect that if you disconnect a good injector, the BLM would go up to somewhere close to 128. The lean condition in that cylinder could somewhat offset the rich condition in the bad cylinder. If you disconnect a bad injector, I suspect the BLM will shoot up over 150.

Any rate, check these things and then report back...

 

Thanks for the responses.

I am running the Southbay Bosch III injectors. I had tunedperformace correct the voltage offsets in my tune as well. so I don't think its the injectors.

The FPR was replaces about 3 years ago by a previous owner. It makes a pretty loud clicky-clack when operating. So ill have to check that again.

I replaced the fuel pump twice two summers ago because the first one failed within a month. Maybe the second one is just now failing.

I have a fuel pressure tester but unfortunately I am traveling and wont be able to check the fuel pressure for a week or so.

If its the fuel pump I'll need to figure out why fuel pumps die so quickly on my car. Whenever I refuel there is always a huge gasp of sucking air when I unscrew the fuel cap. maybe its not vented properly causing strain on the fuel pump causing it to die early. What should I check for venting?

 

A dead fuel pump would go lean - not rich. You are rich and the computer is pulling out fuel (less than 128 is a negative fuel trim).

The Bosch III's usually run lean, not rich, and Tuned Performance is well versed in those matters so you are likely fine on the tune.

You need to figure out where the extra fuel is coming from. Is the O2 sensor pegged rich? You say it's smoking a lot - that could be fuel puddling behind some valves,

Fuel pressure regulators don't typically make any noise - could be sucking fuel in through the vacuum line?

GD

 

BTW, what thermostat are you running? I notice your coolant temp never gets above 160. While I don't think this is necessarily the root of your problem, it's horrendously inefficient. Typically 180F is the minimum you should go with these engines.

 

I think there's a 160 thermostat in it from the previous owner. I'll pick up a 180 from o'reilys and switch it up for sure. Thanks for the suggestion.

As far as the FPR goes I don't think the diaphram is broken because the vacuum line going to it never smells like gas. I'll go through the test in my service manual to see if its still operating effectively

How do I know if fuel is puddling behind the valves? the intake valves are supposed to let the air fuel mixture into the cylinders so how would that be a problem?

 

If you have a leaking injector, it can bleed fuel behind the valves with the engine off. The injectors are bank fired and don't differentiate between valve open and valve closed - they all fire at the same time.

You have a rich condition - be that from a leaking injector, too much fuel pressure, bad O2 sensor, improper tuning, etc - you must determine why.

GD

 

If you have a hand held vacuum pump, you can hook it up to your FPR and pull a vacuum on it and see if it holds.

GD and I are telling you the the things that can cause low BLMs. Something is causing a rich condition so you can't take anything for granted just because they're new... FPR, injectors, etc... you have to eliminate each possible cause until you find it.

I also gave an injector test you can run for free earlier in this thread.

 

Ok thanks for all the tips.

I'll run the tests you both have recommended and ill get back to this thread with the results.

 

Update
So I hooked up the fuel pressure gauge and immediately noticed when the key was in the on position the fuel pressure drops after the 2 seconds of pump operation.

I started the engine and the fuel pressure was great. I shut it off and it immediately began falling pretty fast.

So I followed the diagnosis chart on this and it ultimately led me to a faulty fuel pressure regulator.


It makes sense with what the fuel pressure was doing when I pinched the return line it held solid at 40 psi. as soon as I released it it dropped to 15psi.

The previous owner had replaced the FPR a couple years ago but it just goes to show you cant trust anything you haven't fixed yourself. The FPR was the only thing I hadn't looked at.

Thanks for all your help guys. I'm thinking this should fix my rich condition.

 

Fuel pressure after shut off is meaningless. Fuel pressure only matters when it's running. This is not your problem. Will not fix anything.

GD

 

Plus a failed FPR (in the lower pressure direction) would cause the BLM's to go up, not down. I think of BLM's as the injection pulse time. Smaller number, less fuel. If your BLM's are bottoming on the low end, your ECM is detecting too rich of a condition in the exhaust and trying to lessen fuel. Also, remember we only have one O2 sensor and it monitors the odd cylinder bank.

I would recommend checking your base timing. Make sure it is rock-solid. If it is hopping up and down, your timing chain is worn out.

Lastly, IMHO, the "rope" method is the only way to do the stem seals in these cars. There is also a tool that makes the job tolerable.

 

We're continuing to look for global problems, but It could just be one offending cylinder on the driver side like a leaking injector.

Have you ran through the test I described earlier... disconnecting one injector at a time while idling and watching the BLM's?

From my earlier post...

 

Sorry for taking so long guys. Its been too cold to work outside for the past month or so where I go to college(Kansas). I have done a few things since the last update.

First, I have replaced the intake and exhaust valve seals. The old ones were gone or fell apart in my hands. No more excessive smoke on startup so that's good.

Second, I put in a 180 thermostat so she runs a little hotter.

I also performed the test on the injectors that ULTM8Z described. Whenever I disconnected a injector the car would run noticeably worse and the BLM's did not jump over 128. disconnecting the injectors really didn't have any effect on the BLM readings surprisingly. I gave it a minute or two to adjust to the change after each injector was disconnected but that didn't really change anything either. If I'm interpreting the test correctly this means the injectors are most likely good. A second opinion would be appreciated

During the test my BLM dropped as the coolant temp increased until it was pegged at 108 at an idle. it would jump back up to 128 if there was a throttle increase however.

So if its not the injectors my next thought would be the Fuel pressure regulator given the test I did in December.

Any thought? I think I'm gonna replace the FPR seeing as I already have one ready to go.

 

So I'm assuming that when you were pulling injector plugs, the baseline BLM was 108. Also assuming that you were pulling injector plugs on the driver side (the only side with an O2 sensor).

My guess is that the BLM's would go lower than 108 if the ECM allowed for it. 108 is the lower bound of the allowable fuel trimming range allocated to the ECM.

But, pulling an injector and not going over 128 would actually make sense in that case... while that one cylinder runs lean, everything else is running so rich that one injector going offline is not enough to cause that entire bank to read lean.

Yeah, it also means that your probably don't have one bad injector on the driver side (the only side that can impact fuel trim due to O2 sensor being on that side).

If you already have a new FPR, nothing to lose by installing it and seeing what happens. Though in an earlier post, I was saying you could try putting a hand held vacuum pump on it and seeing if it holds vacuum. Do it to both the old and new FPR's and see if you find a noticeable difference.

BTW, I just recently had my FPR regulator go out. It was the one that came with my Miniram... a modified stock LT1 regulator that TPIS turned into an adjustable. I too got 108 BLMs starting to crop up. I had a stock LT1 regulator on hand and I ran that vacuum test between the two. The TPIS one wouldn't hold vacuum, but the stock one did... telling me the diaphragm failed on the TPIS one. I swapped in the stock regulator and problem solved. Even though the TPIS one was adjustable, I only ever ran it at stock fuel pressure anyway, so it didn't matter.

 

I've had the new FPR in for a few weeks now and there's been no change in drivability. I also used a vacuum pump to apply vacuum to the old one and the new one and they both were similar.

So I'm still trying to find out why the car is running too rich. I think ill take a new data log and see if I can see anything. I think I will put a new O2 and coolant temp sensor in because they're not too expensive at oreilys and I don't know how old the current ones are.