eXpanding my horizons - Fiat content

This probably won't be the most exciting post, but it will help me keep track of what I am doing

Finally dug into the carb Monday night after my book showed up. Carb is a 34DAT w/manual choke

Basically just a refresh and a good cleaning. New float(set to the proper height) and baselined all the adjustments. That's it for pictures, the rest is just going to be me documenting the attempts to dial this thing in.

What I found as delivered:
Idle jets 50/50(drilled out)
Air correction 175/240
F28 tubes
Main jets 120/150
This setup will not idle without quite a bit of throttle screw, and the primary main starts dumping fuel. Idle mixture screw has no effect. Carb surges lightly unless driven with choke on at all times.

I swapped in a pair of F30 emulsion tubes during the refresh based on Xwebforums consensus. Reinstalling the carb showed no change in any symptoms.
In an attempt to make ANYTHING happen, I swapped the idle and progression jets.
50(drilled out)/50
175/240
F30
120/150
This setup will idle down about 1k rpm, but stumbles returning to idle and occasionally stalls. Pretty happy at 1200rpm. The primary is not dripping fuel at idle. The idle mixture screw actually does stuff! No choke needed to run down the road, but the secondary is flat and surges big time.
Just to confirm I stuck a spare 50 back into the idle circuit with no other changes, and the car won't idle, primary starts dumping fuel again.

I stuck a gauge in the drilled out jet and found .035"

Next attempt I wanted to put the .035" back in the progressive circuit because it worked ok there before, but I know the idle won't be happy with a 50 and that's all I have here. Grabbed one of the three 50's and drilled it to .026"
For reference a 50 is 0.5mm = .020"
.026"/.035"
175/240
F30
120/150
This will idle and drive well on the primary. In the secondary, near WOT, things start out ok but falls on its face in the upper rpm range of 3rd gear. Feels lean, can't drive thru it. I hafta push the clutch in and clear the carb. It also surges at certain loads in 4th or 5th down the highway.

Getting late, one last stab for tonight. I swapped the secondary air corrector to a 210 to see if it would richen up the top end
.026"/.035"
175/210
F30
120/150
This made little to no change, maybe slightly worse(earlier in rpm range) at WOT

I am going to do some more reading in this Pat Braden book and am open to any suggestions you guys have.

I'm gloating about your post because I won't have any carbs on my car. Sure, I might spend days upon days with a laptop in my face tuning my EFI, but at least I don't have to do the carb thing.

Gloating aside, I wish I had some constructive advice to offer you here. I suspect you'll find the answers you seek in your book.

   Wonder if the issue is the carb or fuel to the carb.    The pump you used might not work well with the return line.   Also the pump should be mounted as low as practical.   I would also add a pressure gauge and pressure regulator.    At wide open it might be possible you are running out of fuel flow.   Wish I had a picture, but if I recall there is a bracket down by the clutch release stuff, mine is mounted on the underside of that.   I forget what that bracket was used for, I moved some stuff to the rear trunk.  Need to ensure enough fuel but at low pressure.

        If it seems to go lean at the top end secondary, go up several sizes on the secondary main fuel, if that doesn't make it better or makes it worse, then I would wonder about fuel to the carb.

     If I recall correctly, initial tuning for main and main air.   Main fuel is 4 X the venturi size so 34 X 4 or about 136   Main air is main fuel +60  so about 196   So you should be close on the main side.

        I would also go up a size on the carb, you know just for fun, would a 40 DCNF fit?

My rad overflow tank in in the trunk, so you don't have that spot available.  Just for fun a quick test would be to clamp the return line, vise grip, and see what happens.

   Really should get the pump lower, and a fuel pressure gauge would be great to have.

Carb n00b set the float wrong! All better now.

That's excellent news! So all problems solved? Which jets did you land on?

No jetting changes just yet. Drivability is good but I would describe the throttle response more like a butter knife than a scalpel. I plan to experiment with changing jets a bit soon.

Nerf bar project today.

Those bumpers look great!

RossD said:

Those bumpers look great!

Yes they do, and between them, the gold, and the turbines, this has a really nice retro theme. Sweet.

Thanks guys!

The clutch slave decided to puke its guts on my shop floor, so I am in a holding pattern till the replacement gets here Tues. Not happy about it, but better now than during HRPT.

I cleaned a bit today. Put the rearview mirror button back on the windshield that my co-pilot knocked off. Dinked around with the carb to see if I could make it better; it didn't like any of my changes so I put it back.

Maintenanced my daily. It needs more(clutch is in end of life stages, and bearing noise coming from the rear axle) but ain't nobody got time for that. Gonna maintenance the wife's car tomorrow morning. She leaves for Annual Training on the 1st, my daughter is headed to Germany on the 5th, and HRPT for my son and myself begins on the 8th!

Maybe fit the new air cleaner on the Fiat after I change oil in the FoST.

Installed the new slave last night. Would have been nice if some engineer had spec'd a bleeder on the master under the dash....

Got the new air cleaner installed


Both of those complete, it was time for a precipitation test ahead of HRPT. With the remnants of tropical storm Alberto forecast to blow thru today, I put the top on the car when I got to work this morning, rolled up the windows, and crossed my fingers.

Rain started about noon and continued thru nearly 4p.

I came out of work to a very wet engine bay, but a dry seat and only a small amount of water in the floor board. This is acceptable. The engine turned over and fired as if it didn't care a bit about the weather and we were on our way. The trip home was pleasantly uneventful; success!


It is good to know that I won't need to run for cover at the sight of rain clouds during HRPT, and also nice that I don't need to reinstall the rain tray.

Knocked a few items off my punch list today. Getting down to more minor details as long as nothing else breaks!

Started simple and remounted the rear view mirror. I missed it terribly!

I inspected the ignition pick-up wiring at the distributor and found they were indeed flipped relative to info in this thread:

https://xwebforums.com/forum/index.php?threads/wiring-at-distribitor.34543/#post-295418

Put the wires into the proper orientation and reset the base timing.

I went over the carb mounting hardware again, then checked everything for vacuum leaks. All clear so I moved onto fiddling with the jetting.

I'll save the gruesome details of multiple iterations. Here is where I ended up for the day:

50/.026"

175/240

F30

120/150

I have not found the perfect setup yet that allows for good starting and good drivability. I settled on reasonable starting and good everything else. I am going to toss a fresh set of plugs in it and monitor those now that the carb feels close.

Took a couple extended test drives and it felt like power was nosing over about 5k rpm. I retarded the cam timing half a tooth and now it revs better out to 6.5K, and seems to idle a bit smoother to boot.

I had the '76 model. Twin cam 4. I drove it 50 miles a day to work and back, timing belt jumped time 4 times. Each time it did, the valves bent. It was repaired each time by Metric Wrench Garage in Springfield, IL., and the 4 time it happened I gave them the title and received the complete interior for my 850 spyder.

I have since owned Fiero's, but would like to get a dependable X-19.

By the way, Metric Wrench told me that the car was designed to drive short trips at slow speeds in Italy, not the American Highway type of driving.

Here goes everything. Mrs. gumby is off to Nat'l Guard training and I dropped Blockhead G (teenage daughter) at the airport this afternoon for her trip to Germany. That leaves me and Blockhead J (pre-teen son) to finish out the next couple days on our own before we blast-off for Power Tour.

The car is running well and has been getting me back and forth to work rain or shine, mostly without complaint. However, there are still remnants of a punch list to address:

• Oil change
• Spark plugs
• Hang exhaust
• Horn
• Adjust driver's door lock
• Remount driver's harness
• Review and gather packing list items
• Tetris pack all our gear into this tiny car
• Mow grass before we leave?
• Maybe get a haircut?

OK, that is more than enough for 2.5 days. Especially considering I still have to do real work at a real job tomorrow and Thurs. Getting everyone out of the house(my parents were here over the weekend as well), it really feels like responsibilities for this week are over, but au contraire!

After hanging up my airport taxi hat, I headed to the shop and managed to knock the first three items off the punch list before Blockhead J tapped out with hunger pains.

Exhaust hanger as delivered:

New mounts on the muffler

New body mounts and isolators

The supplied bent flat stock hanger allowed the whole exhaust to sag down pretty far. I was able to tuck everything up closer to the rear valance which made me happy. I reshaped the original hanger and kept it installed as a failsafe in case an isolator tears later on.

Figuring it to be in my best interests to keep Blockhead J alive, we made a food run and stopped at the parts store for some hose that I will need to rehab the small air horn set up that came with the car.

CRAP, they found us! I can't take this kid anywhere....

That was pretty much the end of our day. Blockhead J wants to go to work with me and that means getting up early tomorrow, so we called it a night after the parts/food run. I did, however, shoot a quick vid of the car choppin some potatoes before I shut the door

https://youtu.be/b0dagst31_k

In reply to gumby :

That cam sounds really good. Bonus on getting the pipes up higher too.

Love this, you two's be safe @ HRPT

The nerfs  ROCK!!!!!

Got the driver's harness routed, and got the door lock working. Horn is also operational once again.

I started modeling solutions for stowing all our cargo during this adventure. The trunk will carry our duffel bags, no biggie there. The frunk is more my concern. There is a lot of stuff that needs to go in there while still fitting the targa, hopefully being neat, somewhat accessible, and not shifting around while driving. It is an oddly shaped compartment, no doubt. I believe this custom shaped box should hold all the spare parts and fluids I plan to bring along.






Some spare bits I received with the car:


My car has a box similar to the unit on the left. The box pictured has been opened and it looks as though someone planned to put a GM style 4pin module inside the box, a la bbrown. I do not know if it still functions as is, but will likely toss it in the car just in case.
I am curious about the module and wiring in the center. Could someone ID that part for me? If this is complete, as it appears, this could be a simple(side of the road) retrofit to my car. I will need to research the three ring terminal connections and knowing the original application would make that much simpler.

Ill be at the final day of hrpt at zmax. Look for the fat guy in a grm shirt.

Good luck, and have fun!

Also, dad and i learnedon hrpt east in 99 to load all gear and people, then check tire clearance and headlight alignment. We learned that the hard way. Dont be us.

Dusterbd13 said:

Ill be at the final day of hrpt at zmax. Look for the fat guy in a grm shirt.

Good luck, and have fun!

I'll be in the gold Fiat....oh wait....

Dusterbd13 said:

Also, dad and i learnedon hrpt east in 99 to load all gear and people, then check tire clearance and headlight alignment. We learned that the hard way. Dont be us.

I left the nose 1/4" higher than the rear when I cut the coils planning for this very day! So far, so good

    The ignition module in the middle of the picture is what a lot of cars used, I think accel performance ignition makes a version of it.   My Maserati uses the same part, a lot of cars made in 1985 did.    You can connect the fiat distributor to that or use a MSD box.  With the harness you have, I bet the red wire would be 12+ The green would go to coil, and the white cable would go to the distributor.  The advantage, you can easily find a replacement part.

https://www.holley.com/products/ignition/ignition_and_electrical_components/parts/35361

    Found it.....   

Aw, got me all exited there for a minute thinking there would be a drop in aftermarket module, but your link goes to a GM 4pin. 

This module likely performs very similarly to the GM part but the guys on Xweb are pointing to Yugo and my follow up research confirms such. Simple enough to wire in, so it will make a good roadside spare, but a step sideways for parts availability.

I have also seen that either the GM module or an MSD will wire directly to the Fiat distributor. Good info to keep in my hip pocket if plans B and C let me down.

Hot Rod Power Tour 2018 Long Haul completed.

Stories here: https://grassrootsmotorsports.com/forum/grm/hot-rod-power-tour-in-a-fiat/140619/page1/

so awesome. need to read in detail later.

Maybe an update here?

Since returning from Power Tour, I have put many more miles on the X. I eliminated the power valve in the carb on the theory that this cam doesn't produce enough vacuum to pull the PV closed. I never actually proved this out since my vac gauge is missing, but blocking the PV netted and extremely lean idle with no changes to the jetting. So that is some confirmation of an issue. Re-jetted the carb without the PV and have generally just enjoyed having something different to drive when the mood or weather strikes. I even took it out to autoX once when the weather threatened rain

It didn't rain, such is life!


About 6wks ago the radiator decided it no longer wanted to hold coolant and peed all over the driveway. I parked the car for a bit as I was mid-thrash between autoX events with my truck. Pulled the rad and swapped in another unit I got in trade. It leaked in the same location. Pulled that rad out, tossed it in the corner, and took my original to a local repair shop. Unfortunately he sat on it for a month and never touched it. Wednesday morning I ordered up a replacement from MWB and repo'd my original from purgatory.

The replacement showed up Thursday

I have an autoX tomorrow to close out one region, and another next weekend to close out a different region. I need both events to earn class trophies for each region, so it may be another week or so before I get this rad installed and the X back on the road, but I am looking forward to some fall cruising!