Jump to content

No engine start after fuel pump replacement


Recommended Posts

 

My IA installed a new mechanical fuel pump and had to remove Left Mag (Slick 4347).

After all was installed back, engine wouldn’t start.

Electric fuel pump would pressurize but no start and at the end we had some backfire (pooping). Battery and starter (Skytec) run good. It seems everything is connected right now. Originally Retard and P-Lead on LH mag were reversed. Before this I never had had an issue with mags and ignition.

Shower of spark is making noise but we didn’t test (yet) per Don Maxwell’s article. What is the chance of SOS being defective if making noise?

 

Seems left mag could be the issue if SOS is good (we’ll test it)? 

Mags are at 500h so now I’m at the crossroads, what to do. New Slick? Sending for OH or Surefly ignition?

 

My current IA is not equipped to work on mags and would like to send out or replace.

How hard is to diagnose faulty cap or retarding points?

 

My thinking is replace left mag now if I have to (Slick or maybe Surefly) and next annual do the Right mag.

Am I missing something? It could be just coincidence but I find hard to believe that just a removal of the mags would cause the issue…

Thanks.

Edited by Igor_U
Link to comment
Share on other sites

If it worked before it was removed, it may simply be installed and timed wrong.  

No red tooth on a Slick magneto, it uses a timing pin inserted through the distributor block once the wire set is removed.

Clarence

Link to comment
Share on other sites

Interesting on reversing the mag 180 deg.

I was there when it was timed at 25 deg: CYL 1 at TDC using the box and it was on the 25 deg mark on the flywheel. Mag was on it already. 

How would I know it's upside down?

What I've noticed is LHS has label with p/n on top (and the P-lead attachment stud) while RH mag has label with P/N on the bottom, as well as P-lead stud. Is that how they come? I didn't have any pictures of Left mag before.

So, if no red tooth, is it still possible to install it wrong? IA mentioned he marked the the wire set orientation before removal.

2 hours ago, M20Doc said:

If it worked before it was removed, it may simply be installed and timed wrong.  

No red tooth on a Slick magneto, it uses a timing pin inserted through the distributor block once the wire set is removed.

Clarence

 

 

Thank you all.

 

Link to comment
Share on other sites

As mentioned, the slicks don't have the red tooth like the Bendii do.   When the mag is off the airplane is can be positioned to #1 and pinned, and then the engine set to the compression stroke on #1, then the pin removed after installation.   If he marked the cap that should go back on correctly without an issue.    Slick mags are pretty simple and easy to work on, but have some significant differences to the Bendix equivalents. 

Having the timing mark in the right place is still ambiguous to whether the engine is on the compression or exhaust stroke.   Need to do the thumb-on-the-plug-hole trick or something similar to distinguish which it is.   If it is the wrong stroke it won't do anything, consistent with what was described.

 

Edited by EricJ
  • Like 1
Link to comment
Share on other sites

When the timing pin is installed in the magneto, there are 2 holes 1 for right rotation, 1 for left rotation.  The magneto data plate states the rotation of the magneto, the pin is installed in the corresponding hole.  The wrong hole will mess up the timing.

Clarence

Link to comment
Share on other sites

25 minutes ago, Browncbr1 said:

My IA says it is possible to reinstall the mechanical fuel pump without getting the plunger in the right spot so that it won’t pump.   

I remember all of us crossing fingers when we fired mine up the first time after r&r.  

That’s true, but it will start with the electric pump on.

  • Like 2
Link to comment
Share on other sites

Well, electric pump is working and engine monitor (EI CGR30P - taking reading after servo) is in the green as it should. We'll have a look further this weekend. 

12 hours ago, David Lloyd said:

Are you certain fuel is being pumped to the servo?  Problem is either dinosaurs or sparks.

 

Link to comment
Share on other sites

Mags are at 500h so now I’m at the crossroads, what to do. New Slick? Sending for OH or Surefly ignition?

Our factory reman now has 428 hours with annual due in April. I’m leaning towards putting a Surefly on rather than overhaul that one

Link to comment
Share on other sites

  • 3 weeks later...

We finally managed to get together yesterday, removed and installed magneto, timed it and engine still would not start. SOS is seems working...  buzzing sound and all.

With Mag approaching 500h I lean towards replacing LH mag with Surefly. I would really like to do this at annual but I didn't think we can have this mag going without sending it out for OH (or IRAN) as my current IA is not equipped to test and repair mags.

Not sure what's the best to do as I'd like to investigate Surefly more but seems few installs on MS went well and owners like them.

The rub is how can I be sure it's a mag? it was removed and installed with not internals disturbed. El fuel pump works and it showed pressure on Engine monitor when on so engine should start if there's spark, right? Nothing to do with mechanical pump as that one comes online only after  the start...

 

 

 

Link to comment
Share on other sites

Fuel pressure... check...

Air unobstructed... check...

Shower of sparks buzzing... check... (does buzzing always means working properly?) there is room for error here...(?)

Mag timing retard circuit... this is the part of the mag that allows for engine start... it fires off at TDC instead of BTDC....

Often when the ignition switch is held on... and nothing starts... release of the ignition switch allows for the engine to fire...

This is an indication of the one mag not working properly, and the other making up for it when it is brought on line with the ignition switch in the both position...

Sorry for being vague and probably repetitive.... PP trying to add thoughts in a technical area... not a mechanic..

Best regards,

-a-

Link to comment
Share on other sites

I am not too sure how well this work since you said you had slick magnetos., I am not sure if you can mix and match bendix and slick, since I have never heard of any one doing this. but I just pulled my left Bendix S200  that has about 320 hrs on the  Mag off 0360A1D from a'67C and pulled the SOS box. I  installed the Surefly on the left side.

I can NOT yellow tag it but if you want try it for ground run only .... I am about 25 nm south of you \@ KRNT.

James

Link to comment
Share on other sites

1 hour ago, Igor_U said:

We finally managed to get together yesterday, removed and installed magneto, timed it and engine still would not start. SOS is seems working...  buzzing sound and all.

With Mag approaching 500h I lean towards replacing LH mag with Surefly. I would really like to do this at annual but I didn't think we can have this mag going without sending it out for OH (or IRAN) as my current IA is not equipped to test and repair mags.

Not sure what's the best to do as I'd like to investigate Surefly more but seems few installs on MS went well and owners like them.

The rub is how can I be sure it's a mag? it was removed and installed with not internals disturbed. El fuel pump works and it showed pressure on Engine monitor when on so engine should start if there's spark, right? Nothing to do with mechanical pump as that one comes online only after  the start...

 

 

 

You can’t be sure. You had a running engine before the fuel pump replacement, correct?

If so, you had a working ignition system before a human hands got involved and “fixed it”...

The solution is not to throw parts at it.

Given your willingness to replace a mag that was working just a few seconds ago, I’m curious about why the mechanical fuel pump was replaced.

  • Thanks 1
Link to comment
Share on other sites

You don't need fancy equipment to test the mags. Take out at least all the top plugs so the engine will spin freely. Attach the leads to the plugs and lay the plugs on top of the cylinders. Have someone hit the starter and look at the plugs to see if they are sparking. With the shower of sparks, you can move the prop till the points open and you should see continuous sparks.

If you leave the bottom plugs in, blow out the cylinders with compressed air before doing this. If there are fuel vapors in the cylinder, it may light off and make a bang like a shotgun going off. Ask me how I know?

  • Like 4
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.