Having trouble starting the FD after all the replacements below....scratching my head and need a voice of reason.

I have stock twins with the OEM sequential set up, stock injectors and rails, aftermarket Walbro fuel pump, downpipe, and closed cell AGM battery relocated to the passenger bin and currently running stock ECU. Before the below part swaps, FD started up every time with no issues one bit cold or warm...ran like a champ.

Replaced all the solenoids.
Replaced FPR.
Replaced FPD.
New o-rings throughout fuel system and oil filler neck.
Replaced all new vacuum lines.
Sent the injectors (primary and secondary) out for cleaning and servicing, came back great.
New spark plugs and new plug wires.

After the first attempt on re-installing the injectors, buttoned things up and ran the fuel pump from the service connection port on the drivers side of the bay (wire from the fuel pump section to the ground), noticed there was a leak on one of the secondary injectors. Pulled apart, replaced the o-rings and re-installed properly. Ran the fuel pump again and there were no leaks.

Put everything back together (was very meticulous with connectors, solenoids, and vacuum lines following wiring diagrams and vacuum diagrams). Went to crank it up and it just turns but nothing firing up.

My first thought was that maybe I flooded the engine by testing the fuel pump when I re-installed the injectors, so I did the de-flood test. Put the plugs back in and nothing...Pulled the plugs and tested each plug and wire for spark, which they all had solid spark.

Before I pull things back apart and essentially verify all connectors and lines...I feel like I'm missing something very simple? Is it possible to absolutely insano flood the engine? I probably ran the fuel pump for a collective 60 seconds during the fuel rail and injector installations.

Any advice or quick tips is much appreciated!

-milly

 

Check the battery to make sure it has enough cranking amps tp spin the motor quick enough. Some batteries dont cut the mustard for the FD.

 

Could be that your just-cleaned primary injectors are sticking closed. Happened to me, with the secondaries.

 

Yes it is possible to insanely flood the engine.

We spent 30 hours trying to unflood the engine on my car.

Turned out, in the end, I had got a bad tank of gas.

Coils had spark, but were still weak.

In the end we had to the flood the intake with air to overcome the flooded condition.

We did this by removing the ISC and having a tech use his hand as a throttle plate over the isc port.

 

 

We did not want to move the throttle, as the TPS would register the throttle opening and the ecu would increase the injector duty.

It was likely that I did not have vacuum to the FPR, which would then have been closed, increasing the fuel line pressure to the injectors.

After getting the car running, we pulled the injectors to have them serviced. They were running at 65%.

The ecu was likely tuned to that condition of the injectors.

It is running me rich now that the injectors have been refurbished.

 

Just to be clear, it cranks OK but doesn't start, correct?

And when you pulled the plugs to check for flooding, did you see any evidence that fuel is getting to the combustion chambers (i.e., plugs wet and/or fuel stink upon plug removal)?

If the answers to the above 2 questions are YES and NO, respectively, I'm thinking the issue is electrical - with all the disassembly work you've done, you may have somehow missed reconnecting a common ground or a connector that feeds power to the associated fuel injectors or ignition coils. It's been a million years since I touched an FD with a stock wiring harness, but if there are any ground lugs dangling off the harnesses in any of those areas you worked on, they need to bolt to the block somewhere.

Another possibility is while you were in there you may have inadvertently damaged wiring to the CAS sensors - engine won't start but will crank if the ECU isn't getting a good signal from the CAS.

 

Thanks for the replies here all..catching up with the holidays.



Yeah battery is solid.

Can you explain this in greater detail and what you did to remedy this? Did you test them out of the motor?

That was a crazy noise during that video coming from the motor. Can you elaborate what the ICS is?

I feel like you may be correct on this one...I will most likely pull things apart and check all the connectors and wires again. Few connector tabs cracked when removing them and had to fix a few already. To answer your question is does crank but not start. When I pulled the plugs it seemed like there was fuel in there, but they were not absolutely soaked. Probably going to pull them again and see.


Thanks again to all.

 

Hit it with a shot of starting fluid into the throttle body, if it starts then you know it's fuel related.

How long was the car apart for?

 

I'll give that a shot.

Car was apart for about a month and change.

 

The ISC is the idle speed control. It is what the ecu uses to control air flow to bypass the throttle body.

It is a robust device but they can stick open/shut or otherwise have an electrical failure of some sort.

New ones cost about $400, but usually used ones can be got for $75.

Yeah that is the internal noise your engine is making that is muffled by the UIM.

With the ISC off the UIM is wide open for you to hear.

Quite surprising.

The method I describe above has a risk of running the engine too lean, so other methods be best used first.

Note: When deflooding we disconnected the electrical connector that sits above the fuel pump access panel.

If you look at the wiring for the fuel pump, it seems to have redundant routes.

We did not trust that somehow the fuel pump was still getting power when we did the relay and fuse pull methods to shut it off..

The witch doctor among our techs did not trust plugs that had been deeply flooded, even if they looked dry. So we replaced the plugs about four times.

We cleaned out the supply in the city.

 

To get to the end point, which was to take a whiff of the gas (smelled more like water) we checked over almost everything and swapped in spare devices, including trying a substitute Power FC.

The next day we were going check the CAS (Crank angle sensors, including the clearance of the trigger wheel (mine wobbles), but we got it started that night.

The gas station claimed no issue of other complaints with the "94" gas. They did mention that newer car's ECU could handle a wider range of octane fluctuations.

Also local refiners had only been required to add ethanol from about 6 months prior, and they may have still been learning proper storage of the mixed fuel.

 

In hindsight, the ECU had likely been dealing with many devices moving gradually off spec and the weak fuel was a final hurdle it could not adjust to.

The MAP sensor and TPS we replaced were testing somewhat off spec.

We kept the battery on tender to handle all the cranking.

Of note as well: New solenoids may come out of spec out of the box. They may have been kicking around shops parts bins for some time.

 

^That's pretty common with 30 year old brittle plastic connector shells that went thru 1000's of heat cycles. Besides the the lock tabs breaking, another harder to see but ultimately more important thing to check with connectors is that the metal terminals are still securely anchored in the plastic back shell. If the metal terminals are not secured or aligned properly, the act of mating the connectors will force one or both of the terminals to push back out of the connector shell, where they don't make good electrical contact.

Sounds like your getting fuel into the combustion chamber, but that doesn't necessarily mean its getting flooded - depends on how much time elapsed between your cranking the engine over and pulling the plugs.

 

Well I hit it with some starting fluid and it tried to start for half a second and then failed. Must be fuel related then if it’s not getting fuel like I thought.
Going to pull it back apart and see what’s going on. Maybe a loose connector or a clogged injector as stated above.

 

Well pulled everything apart again today. Saw another member post about stuck lintels on their injectors after a service from RV Engineering.

Tried the 9V battery trick on each injector and nothing is clicking. Probably give RC a call and see about sending them the injectors and fuel rail so they can re test and confirm things are working.

TBD…

 

Years ago I sent out my injectors for cleaning, and it took me about a month to get the car back together. Primaries were fine but the secondaries were stuck tight. Had never experienced that before with other cars and I tore my hair out trying to figure out what was wrong before I read a post about how the solvent can cause the injector to stick closed. Installed a new set of secondary injectors which fixed the problem.

Still don’t understand why it happens on FD injectors and not other cars.

 

It does happen on other injectors - it's frequently noted in racecar forums that cleaned injectors left in open air after cleaning often fail to work when installed. Apparently the common cleaning/testing fluid turns to varnish or similar when left unused and exposed to air for more than a week or 2.

The company that does mine ( Mumm Brothers Racing Fuel Injector Service,http://www.mummbrothers.com/Fuel_Inj...inPage_FIS.htm ) packs them in a vacuum-sealed foil bag to prevent this. I've had no issues with injectors sealed off from air in that manner even after years of storage.

 

I've heard about this sort of problem on other cars also, and I agree the cleaning solution or test fluid is likely a factor. I've had used injectors that were removed from cars and stored in a box indoors for years (without cleaning solution / test fluid), and they still worked without getting stuck. You might be able to unstick yours by running some MAF sensor cleaner fluid through them, while connecting 12V to cycle the solenoids. But it might be best to mention to RC Engineering that yours seemed jammed and ask if they can clean them again. If they can change their process to avoid other people's injectors getting jammed, that would be the best case scenario.

 

Yes, it would, but the cleaned injector sticking issue has been around for at least 20 years (since I started racing using an injected engine and paying attention to that), and I would think that if it were easy/inexpensive to correct, we wouldn't still be seeing these issues.

 

Well as an update here I did send my injectors and entire fuel rail setup back to RC Engineering. Should be getting them in a day or two back, but they did confirm that the secondaries were stuck closed.

Excited to get them back in and see if she cranks up! Will report back with updates.

 

Pick up a spare set of secondaries in any event.

 

Does the stock ECU utilize the secondary injectors during start up, or even low load conditions?

 

I do not believe so...I read that they come on after 2750 RPM give or take. But that startup/idle issues will occur if the secondaries are stuck. I know also the O-Rings are super finicky when you install everything and it's easy to smash them all up...got them buttoned up finally last night. Hope to try to start everything tonight and see what shakes out.

 

You definitely have to lube the injectors to keep injector o rings from rolling during install. I had an injector seal roll during install years ago. Upon first fire up on a new rebuild everything was going smooth. 15 minutes into idling and all of a sudden a huge engine fire erupted. Luckily put it out with very minimal damage and determined upon disassembly that a primary injector was leaking very slightly due to a rolled o ring and was filling the cavities on top of the engine block. Everything was fine until it spilled over onto the manifold. From then on I use plenty of lube and haven't had an issue.