General Information > FAQ/Tech Tips/Please Read First

2010 Edition of the Governor Mod

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I Stole this from the Vortex Diesel section, as our DIY section got kinda messed up when we did the forum change in 2009. Not to mention our Governor Mod page in the FAQ is 5 years old, has outdated methods, broken links and simply tells the readers to shim the wrong springs. Black Smokin' Diesel did a wonderful prep and writeup about the governor mod, however some pics he used shows shimming of the wrong springs as well. I did a little editing among the thread to reflect the best way to do the governor mod. Full credit to Black Smokin' Diesel and fspGTD for the pics and information. ENJOY  ;)

There has also been a ton of banter about which is the correct way to do this. Some remove the intermediate spring and put in a solid piece, and still shim the main spring.. as the creator of the pictures did. However from talking to a few people who have done this recently both ways.. touching the intermediate spring will make the car very weird to drive under normal conditions.

--- Quote from: theman53 ---What I noticed was when you mash it in first you had to shift before you thought it was going to blow. 2nd same, 3rd same. It would keep pulling as long as the rpms were still climbing. 4th and 5th usually were way over the speed limit and still pulled well, not quite as good as the lower gears.

From what I gather the main spring compresses a little on low RPM, but mainly it is the higher RPMs that it affects. I never had a tach, but I am guessing about 2,500 the main spring starts to limit fuel and will continue until 4,800-5,300. Then I don't believe your engine will rev anymore because of lack of fuel. You should feel it when driving that you lose power even though the engine keeps spinning faster. When you mod it it will go until valve float...or at least that is what is sounded like to me.
--- End quote ---

--- Quote from: theman53 ---yes above idle it is the intermediate spring doing much of the work...but you need it to. If you shim it or put a solid piece in it will cause driving issues. If you hold the pedal in one spot and the intermediate spring has a different load put on in *rolling hill for ex.* then your rpm will go up then down without moving the  pedal at all. It feels like you don't have a direct connection to the car it does what it wants. I suspect the firmer the intermediate spring the worse it would be.

--- End quote ---

--- Quote from: dts67 ---If you take the lever in both hands and pull it you'll see how it works, at WOT the 2 smaller are fully compressed anyway, shimming them makes no gain imo, only ruins part throttle and idle control.
--- End quote ---

So as you can see from user experience, just shim the damn Main Spring and be done with it and enjoy the new found power that has been unlocked from your BEAST!  ;D ;D

I am not responsible for any damage that could occur to your pump, engine and car before, during and after this modification.

There's a lot more to IDI tuning than this. I suggest you educate yourself about IDI engines before you do any mods to your pump/engine. Before attempting this mod, you should be armed with technical information on the VE pump.  I have been collecting this over a few years time, scanning it in and putting it linked to this page.  Here you will find descriptions on how the pump works, related terminology (what its parts are called) and useful detailed parts blow-up diagrams:
Read and study these links well before attempting going inside your own VE pump.

Ah the infamous governor mod! IDI's Achilles' heel. It's amazing how such a simple (relatively speaking) procedure can yield such impressive results.

What does it do and how it works
The governor is used to control RPMs and fuel delivery. When reaching full throttle, fuel is gradually cut by 80% and RPM is limited to about 5500. Modding the governor means a LOT more fuel in most of the RPM range and higher revs (some people have taken their 1.6 to 6000 and more).

The governor is a simple device. Three springs and a cage. There's the Idle, Intermediate and Main spring. When you rotate the throttle on the IP, the governor pulls on a lever inside the pump. This lever increases RPM and fueling to a certain point. That certain point is determined by the governor which stretches when pulled. Once the throttle reaches the stop screw, the governor has stretched enough to cut fuel by 80%.

Starting from the left: Idle (small), intermediate (medium) and main (long) spring. The shaft on the right is the throttle shaft.

How the mod works
The mod will prevent the governor from stretching by NOT touching the intermediate spring and instead shimming the main spring with 3-5mm. The small idle spring is left UNTOUCHED.

This is what it will look like when modded. The original poster did not have a picture of exactly what I wanted to portray.. so a little Microsoft paint and Voila! The main spring (far right) is to be shimmed with 3-5mm of washers that will fit on the shaft and in the cage.

What you need to know
The engine should be in top shape and correctly timed. Steps 1-4 really only apply to turbo equipped engines.

First and foremost, increasing fueling will yield higher EGT (exhaust gas temperature). An EGT gauge is highly recommended. On Turobo engines to use this fuel, you'll need to up the boost. Blocking the BOV on the intake, installing a manual boost controller and adding a boost gauge is necessary.

Second, to keep EGTs down you'll want an intercooler. Ebay is a great source for cheap coolers, aluminum tubing and silicone couplers. If you're doing this to a NA engine, water injection might be something to look into.

Third, the stock exhaust simply won't cut it. 2.5" front to back is a good size. Straight pipe (no mufflers) is ok, it shouldn't be too loud.

Fourth, headgasket. Since you'll be upping the boost, the stock HG might not last long. If you have to replace it, now would be a good time. Here's a link to the metal HG upgrade for hydrolic 1.6 engines:

Fifth, you will want an RPM gauge if you don't have one. This mod will allow the engine to rev itself until it floats valves and throws a rod out through the side of the block.

If you can, remove the pump from the engine. It'll make the job a lot easier but is not necessary. Clean the injection pump really good! Brake cleaner works nicely. You don't want crap to fall into the pump, it has very tight tolerances. If you can get your hands on a pump rebuilt kit it would be best as you will have to replace one or two seals. Work in a clean area and lubricate everything with clean diesel fuel.

The procedure
This it the test subject. An old seized pump I kept for spare parts. I didn't bother cleaning it since its governor will be installed in a working pump.

Note the position of these springs before disassembly and mark the orientation of the throttle lever.

Unhook the spring from the throttle lever and remove the top 10mm nut. Gently tap the lever and pry it off the shaft. You don't need to separate the two levers like I did.

Remove all the springs and their seat from the shaft. Keep them in order (mine will go back from right to left).

There are four allen bolts holding the cover on. One of them is under one of the throttle lever's stop screw. If you can't remove the stop screw easily, unscrew the locking nut halfway. Take the throttle lever's top bolt, thread it on the stop screw and resting it against the locking nut. They should lock together and enable you to move the stop screw. If one of the allen bolt strips, use a bigger torx bit and hammer in in the bolt. You can see the stop screws on the right in this picture.

Once the bolt are off the cover will pop up. Unhook the spring on the left (don't lose it) and gently tap on the throttle shaft to slide it out of the cover.

This is what you'll see when the cover is off. The small spring you unhooked is used by the cold start advance. The rectangular seal on the cover will have to be replaced along with the small rubber o-ring on the throttle shaft. The governor is attached to the throttle shaft.

Grab the governor and rotate it so the notch on the shaft clears the notch on the lever.

Governor removed. You can clearly see the small rubber o-ring you'll have to replace on the throttle shaft.

To disassemble the governor (note that you cannot remove the throttle shaft, it is riveted onto the governor), press on the Grey spring seat to compress it and slide it out of its cage.

This is what you end up with.

Remove the small cir-clip at the main spring end of the governor. You'll have to slightly compress the main spring to get it off using a small flat head screwdriver. Be careful as the spring and seat could fly out in your face and take out your left eye.

Remove the spring seat and the Main spring. Use the appropriate washers to shim the main spring (pre-loading it). When reassembling the Main spring, you'll have to compress it to fit the seat and it's circlip onto the shaft. It might be hard to compress due to the shims. Be careful and make sure the circlip is fully engaged into its groove. Slide it back into the cage. It'll will be hard to compress to make it fit so take your time and be careful. Make sure it's completely seated and that everything is in its appropriate order. This picture is also wrong as to what to do.. but it was how the original poster did his shimming.. not how we want to do ours! Do not touch the Intermediate spring or shim it at all.

Reassembly of the pump is the reverse of dissasembly. Clean the governor and the mating sides of the pump and cover. Replace the cover seal and the throttle shaft o-ring. Slide the governor back into place into its notched lever. Lube the inside of the throttle hole on the cover and the throttle lever and o-ring with clean diesel (don't use any kind of grease). Carefully slide the throttle lever into the hole in the cover. Don't force anything. Don't worry if it's not in completely, you can pull on it from the top. Next, hook back the cold start spring to its lever.

Torque down the allen bolts on the cover (don't go crazy, they're steel bolts threading in to aluminum). Reassemble the throttle levers making sure they are in the same orientation as before.

Now go out there and have fun with your newly found power. Don't forget, modding is a step by step thing. Don't go out modding every setting on your pump all at the same time. Tune one setting and see what it does then move on to the next.

May 17th 2011- I did the Gov Mod today. ;) Yes I wrote this DIY over a year ago with no actual inside knowledge of the Bosch VE pump lol.

The top cage assembly is for my 91 N/A, and YES that is a shim that takes up THE ENTIRE MAIN SPRING SPOT! I wish I measured it.. come to think of it..

Couple of pictures regarding spring placement, I'm glad i took these.. cuz NO WAY I remembered what they looked like.. and the way they wrap around doesnt make sense lol.

Anyway, now I have viable %100 proof and not just word from other people. This MOD WORKS. I shimmed the main so that it doesn't move at all, and I have zero drivability issues, and still fully functional pump.

You want proof? Here it is. Before with my 185/60/14's on my FN trans 3.89FD and 1.29 3rd gear wouldn't be any good past 85km/h (3900rpm).. sure it still had some left, but you needed to be in a wind, down a hill, or just want to wind it out for 2 km's to gain another 10km/h..  NOW 3rd gear pulls all the way up to 115km/h!!! (5300rpm!!) 4th gear up to 140km/h and 5th got me up to 155km/h. All on flat ground with not much wind to speak of today, and it didn't take nearly as long.

Oh and I most certainly had 2nd gear wound up to 80-85km/h in town.. (5600-5900rpm's)


EDIT: March 6th 2012. I have good knowledge that shimming the governor too aggressively will cause internal pump wear. Nothing to be extremely worried about, but just letting you know it can happen.

The added spring tension on the throttle lever towards the governor shaft will aid in the wear on the throttle plate where the governor shaft rides.

Nice work!

Be prepared to drop the clutch to stall the engine in case you really screwed something up. The stop solenoid should be able to turn the car off but just in case it's good to have a backup plan.

Very good write up clarifying the gov mod.
I know when i first went about searching for it, the many different views had me confused. I eventually did just shim the main after extensive reading!
Nice to have it clear and concise in one thread.

The only thing I noticed was I had my pump a lot cleaner when opening. I know you cabbaged the pics, but it is worth noting that these pumps don't like much of anything in them that isn't burnable. I used at least one can of brake clean after hosing off the big stuff before opening.
Other than that I think this thread FTW on the governor mod


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